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Heating and cooling
Unit guide
Where this unit fits in
Prior learning
This unit builds on:
ideas introduced in unit 4C Keeping warm and unit 5D Changing state in the key stage 2 scheme of work,
unit 7I Energy resources, unit 7G Particle model of solids, liquids and gases, pupils will have encountered
the particle model of matter.
To make good progress, pupils starting
this unit need to understand:
• the particle model for solids, liquids
and gases
• that energy can be transferred.
The concepts in this unit are:
temperature, expansion and contraction, thermal energy transfer.
This unit leads onto:
unit 9I Energy and electricity, covering energy transfers and energy conservation.
Framework yearly teaching objectives – Energy
• Describe energy transfer as the result of temperature difference and use this to explain that:
– heating is a process where energy is transferred – temperature change is the response of the material to the energy transfer
– radiation is a means of energy transfer which does not directly depend on the movement of particles.
• Use the particle model of solids, liquids and gases and energy transfer to explain:
– the processes of conduction, convection, evaporation
– what happens when substances change state
– the performance of thermal conductors and insulators.
Expectations from the QCA Scheme of Work
At the end of this unit …
… most pupils will …
… some pupils will not have made so
much progress and will …
… some pupils will have progressed
further and will …
in terms of scientific enquiry NC Programme of Study Sc1 2c, d, g, h, i, j, k, l, m, o, p
• plan a survey of perceptions of temperature, using an
appropriate sample
• plan an investigation into methods of reducing heat loss
• carry this out using ICT for recording temperature data
and relate findings to practical implications
• select effectively information from secondary sources to
compare methods of preventing heat loss in houses
• collect and interpret temperature data from a substance
changing state.
• use thermometers safely
• make systematic measurements of
• present survey data using a chart or table
temperature changes with a precision
• identify and control key variables in an
which enables reliable conclusions to be
investigation of insulators for reducing
drawn in an investigation of insulators
heat loss and draw practical conclusions • evaluate different sources of information
• select information to report on ways of
on domestic heat loss prevention methods
reducing heat loss in houses
• extrapolate from temperature data on
• draw a graph of temperature changes
change of state.
when a substance changes state.
in terms of physical processes NC Programme of Study Sc4 1a, b, d, 2c; Sc4 5d, e, f
• give examples of common temperatures on the Celsius scale
• distinguish between heat and temperature
• describe energy flow as the result of temperature difference
• describe some uses of good conductors and insulators and
examples of conduction in solids and convection in liquids
and gases
• explain conduction and convection, expansion and change
of state in terms of the particle model.
• give examples of some common
temperatures
• describe some uses of good conductors
and insulators;
• describe how insulators can reduce heat
loss
• describe how substances expand and
change state.
• give examples of a wide range of
temperatures on the Celsius scale
• compare conductivity of materials and
relate this to their uses
• use the particle model to explain change
of state relating this to the forces
between particles.
Suggested lesson allocation (see individual lesson planning guides)
Direct route
I1
What
temperature?
I2
Temperature
and energy
I3
Bigger and
smaller
I4
All change
I5
Conduction
I6
Convection
I7
Evaporation,
radiation
I8
Explaining the results –
Think about variables
Extra lessons (not in pupil book)
Review and assess progress
(distributed appropriately)
Additional information
The emphasis in some of these lessons may well depend on the time of year, whether keeping warm or cool seems most important to pupils at the time.
Misconceptions
Pupils frequently believe that particles expand, rather than get further apart; and that liquid particles are further apart than solid ones. The average
spacing is increased but this is because the liquid particles are arranged randomly.
Health and safety (see activity notes to inform risk assessment)
Many of the practicals involve heating objects. Normal laboratory safety practice is required but care should be taken as heated objects (metal bars,
tripods) do not look hot but may remain so for some time.
© Harcourt Education Ltd 2004 Catalyst 2
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What temperature?
I1
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Lesson planning
guide
Learning objectives
i
Our perceptions of ‘hot’ and ‘cold’ are subjective.
ii
Thermometers allow us to measure temperature objectively.
Scientific enquiry
iii Different types of thermometer are used to measure temperature.
Suggested alternative starter activities (5–10 minutes)
Introduce the unit
Share learning
objectives
Problem solving
Capture interest (1)
Capture interest (2)
Unit map for Heating and
cooling.
• Find out why we need
thermometers.
• Be able to use different
kinds of thermometers.
(Sc1)
Use feeling in hands to
decide how hot a bowl of
water is to demonstrate the
need for a standard scale.
Show different
thermometers, discuss
their uses. Or use photos.
Catalyst Interactive
Presentations 2
Show photos of different
scenarios relating to
heating and cooling.
Catalyst Interactive
Presentations 2
Suggested alternative main activities
Activity
Learning
objective
see above
Description
Approx.
timing
Textbook I1
i, ii and iii
Teacher-led explanation and questioning OR pupils work individually,
in pairs or in small groups through the in-text questions and then
onto the end-of-spread questions if time allows.
Act I1a Practical
i
Making a thermometer Pupils make a simple water thermometer and 20 min
use it to measure temperature.
15 min
Target group
C
H
E
S
R/G
G
R
S
✔
✔
Suggested alternative plenary activities (5–10 minutes)
Review learning
Sharing responses
Group feedback
Word game
Looking ahead
Pupils discuss why we need
thermometers.
Teacher-led discussion of
outcomes from Activity I1a.
In groups, pupils list
different kinds of
thermometers, and say
where each would be used.
Pupils play hangman with
Remind pupils of the
the names of different types particle model by arranging
of thermometer.
groups of pupils to model a
solid and then a solid given
more energy to vibrate.
Learning outcomes
Most pupils will …
Some pupils, making less progress
will …
Some pupils, making more progress
will …
• give examples of a range of temperatures on
the Celsius scale
• plan a survey of perceptions of temperature,
using an appropriate sample
• realise that the sensation of cold is because
energy is leaving the skin and the sensation of
warmth is because of energy entering the skin.
• give examples of some common temperatures
• use thermometers safely
• present survey data using a chart or table
• realise that you cannot use your skin to
measure temperatures reliably.
• give examples of a wide range of temperatures
on the Celsius scale
• also use thermometers with precision
• also understand that cold is the absence of
thermal energy.
Key words
temperature, degrees Celsius, ºC, thermal (heat) energy, energy, red only:
absolute zero
Out-of-lesson learning
Homework I1
Textbook I1 end-of-spread questions
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Temperature and energy
I2
Lesson planning
guide
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Learning objectives
i
Realise that there is a difference between thermal energy (heat) and temperature.
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Scientific enquiry
ii
Use a model to develop understanding. (Framework YTO Sc1 8a)
iii Carry out experiments with two input variables (energy supplied and mass) and one outcome variable (temperature rise). (Framework YTO Sc1 7c)
^ _
Suggested alternative starter activities (5–10 minutes)
UG
Recap last lesson
Share learning
objectives
Problem solving
Capture interest (1)
Capture interest (2)
Pupils work in pairs to
answer questions on the
pupil sheet about different
types of thermometers.
• Be able to explain the
difference between
thermal energy and
temperature.
• Carry out an experiment
where there are two input
variables and one output
variable. (Sc1)
Pupils suggest whether a
steaming kettle or a bath is
at the highest temperature
and which has the most
heat energy.
Demo the food-burning
experiment with two
different quantities of
water.
Demo of different amounts
of energy being put into
the same volumes of water.
Suggested alternative main activities
Activity
Learning
objective
see above
Description
Textbook I2
i and ii
Teacher-led explanation and questioning OR pupils work individually,
in pairs or in small groups through the in-text questions and then
onto the end-of-spread questions if time allows.
Activity I2a Practical
i and iii
Activity I2b
Catalyst Interactive
Presentations 2
Approx.
timing
Target group
C
H
E
S
20 min
R/G
G
R
S
Energy and temperature Pupils find out how much energy is needed
to heat different volumes of water by 10oC
30 min
✔
✔
✔
Support animation to the ‘particles’ in beakers of water at different
temperatures.
5 min
✔
Suggested alternative plenary activities (5–10 minutes)
Review learning
Sharing responses
Group feedback
Word game
Show the pupils the
learning objectives again.
Ask volunteers to explain
how the lesson has helped
them to achieve the
objectives.
Pupils answer questions
about Activity I2a.
In groups, pupils complete Play the Taboo game.
the sentences about the
difference between heat and
temperature.
Looking ahead
A small group of pupils
model a solid as heat
energy causes increased
vibration and expansion.
Learning outcomes
Most pupils will …
Some pupils, making less progress
will …
Some pupils, making more progress
will …
• realise that temperature change depends both • know that supplying the same amount of
• also develop an understanding that
on the energy supplied and the number of
energy does not always give the same
temperature is the average energy per particle
particles present
temperature rise
• also use their ideas about temperature to
• consider the interaction of more than one
• decide which experiments need to be compared
predict the outcome of experiments involving
input variable (mass and energy transferred)
to give a fair test.
heating.
to produce one outcome variable (temperature
rise).
Key words
none
Out-of-lesson learning
Homework I2
Textbook I2 end-of-spread questions
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Bigger and smaller
I3
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Lesson planning
guide
Learning objectives
i
Relate changes in temperature to changes in the movement of the particles
ii
Understand that expansion on heating can be explained in terms of the movement of particles.
Scientific enquiry
iii Use the particle model to explain expansion. (Framework YTO Sc1 8a)
Suggested alternative starter activities (5–10 minutes)
Recap last lesson
Share learning
objectives
Brainstorming
Problem solving
Capture interest
Pupils complete the
sentences read out to them
about temperature and
energy.
• Find out what happens
when something is heated
or cooled.
• Describe some examples of
heating causing expansion.
• Use the particle model to
explain heating and
cooling. (Sc1)
Pupils suggest examples of
times and places where
things expand or contract
when the temperature
changes.
Demo how a tight screw cap
can be taken off a bottle.
Demo the heating of a
bimetallic strip.
Suggested alternative main activities
Activity
Textbook I3
Learning
objective
see above
Description
i, ii and iii
Teacher-led explanation and questioning OR pupils work individually,
in pairs or in small groups through the in-text questions and then
onto the end-of-spread questions if time allows.
Approx.
timing
Target group
C
H
E
S
R/G
G
R
S
20 min
Activity I3a Practical
i, ii and iii
Expansion in solids Pupils watch ball and ring and metal rod
demonstrations of solids expanding and contracting.
10 min
✔
Activity I3b Practical
i, ii and iii
Expansion in gases Pupils observe what happens to a column of air
at different temperatures.
10 min
✔
Activity I3c Paper
i, ii and iii
Expansion in liquids Pupils analyse results of liquids expanding by
different amounts and look at what happens when water freezes.
10 min
Activity I3d
Catalyst Interactive
Presentations 2
i, ii and iii
Support animation of particles in solid, liquid, gas as the substances
expand.
5 min
✔
✔
Suggested alternative plenary activities (5–10 minutes)
Review learning
Sharing responses
Group feedback
Word game
Looking ahead
Pupils answer questions
with one (or two) word
answers with white boards,
or volunteer answers.
Whole-class feedback on
Activity I3a or Activity I3b.
Pupils produce a poster to
explain why a thermometer
works.
Pupils pair observations
with explanations correctly.
A small group of pupils
model a solid turning to
liquid and turning to gas.
Learning outcomes
Most pupils will …
Some pupils, making less progress
will …
Some pupils, making more progress
will …
• understand that increased movement of
• know that particles vibrate or move more when • relate temperature to the kinetic energy of
particles (vibration or translation) causes an
they are heated
the particles
increase in temperature
• describe how substances expand.
• also relate the particle model and expansion
• use the particle model to explain expansion in
to changes in density.
solids, liquids and gases.
Key words
expand, contract, red only: dense
Out-of-lesson learning
Homework I3
Textbook I3 end-of-spread questions
Activity I3c
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All change
I4
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Lesson planning
guide
Learning objectives
i
Know that the temperature of a substance stays constant during changes in state.
ii
Relate this to the particle model.
Scientific enquiry
iii Measure temperature changes during changes in state and present the data using line graphs. (Framework YTO Sc1 7d, f)
iv Use a scientific model to explain observed phenomena. (Framework YTO Sc1 8a)
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UG
Suggested alternative starter activities (5–10 minutes)
Recap last lesson
Share learning
objectives
Play ‘Give me five’. Ask
• Find out what happens to
pupils to give five examples
temperature as things
of things that expand when
change state.
they are heated, or contract • Be able to explain what
when cooled.
happens during a change
of state using the particle
model. (Sc1)
Problem solving
Capture interest (1)
Capture interest (2)
Show a cooling curve for
gold. Ask pupils to describe
what information they can
get from the graph.
Show a drink with ice cubes
and a thermometer and ask
for predictions about how
long this drink will stay at
the same temperature.
Pupils are asked for the
opposites of melt and
condense and to explain the
difference between melt
and dissolve.
Suggested alternative main activities
Activity
Learning
objective
see above
Description
Approx.
timing
Textbook I4
i, ii, iii
and iv
Teacher-led explanation and questioning OR pupils work individually,
in pairs or in small groups through the in-text questions and then
onto the end-of-spread questions if time allows.
Activity I4a Practical
i, ii, iii and
iv
Activity I4b
Catalyst Interactive
Presentations 2
i, ii, iii and
iv
Target group
C
H
E
S
20 min
R/G
G
R
S
Changes of state Pupils observe a liquid turning to a solid and
analyse the cooling curve.
20 min
✔
✔
✔
Support animation showing changes of state
5 min
✔
Suggested alternative plenary activities (5–10 minutes)
Review learning
Sharing responses
Pupils write definitions for
Whole-class discussion of
words relating to changes of the outcome of
state.
Activity I4a.
Group feedback
Problem solving
Looking ahead
In groups, pupils annotate
the graph and explain to
each other why the
temperature stays the same.
Ask pupils why a steam
burn can be much more
serious than one from
boiling water.
A small group of pupils line
up as particles in a solid
and link arms, the end one
is heated and vibrates,
vibrations are passed along
to model conduction.
Learning outcomes
Most pupils will …
Some pupils, making less progress
will …
Some pupils, making more progress
will …
• review their knowledge of the particle model
for solids, liquids and gases
• with guidance, begin to use the particle
model to explain changes in state
• collect and interpret temperature data from a
substance changing state.
• begin to use the particle model to compare
solids, liquids and gases
• describe how substances change state
• draw a graph of temperature changes when a
substance changes state.
• use the particle model to explain change of
state relating this to the forces between
particles
• also predict the shapes of graphs for heating
experiments that involve changes in state.
Key words
states of matter, changes of state, red only: forces of attraction
Out-of-lesson learning
Homework I4
Textbook I4 end-of-spread questions
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Conduction
I5
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Lesson planning
guide
Learning objectives
i
Learn that thermal energy can be transferred from particle to particle.
ii
Relate this knowledge to the arrangement of particles in different materials.
Scientific enquiry
iii Use models to explain thermal energy transfer by conduction. (Framework YTO Sc1 8a)
^ _
Suggested alternative starter activities (5–10 minutes)
UG
Recap last lesson
Share learning
objectives
Problem solving
Capture interest (1)
Capture interest (2)
Play ‘It’s on the tip of my
tongue’ with words for
changes of state.
• Find out about
conduction.
• Use the particle model to
explain conduction.
• Describe materials as
conductors or insulators.
Show pupils some examples
of saucepans and ask them
to suggest why they have
metal pans and wooden or
plastic handles.
Demo ice trapped by gauze
at the bottom of a test
tube with a Bunsen burner
heating the water at the
top to boiling point.
Volunteer pupils stir sugar
into beakers of very hot
water, one with a plastic
spoon and one with a metal
spoon. The class predicts
what the volunteers will
feel.
Suggested alternative main activities
Activity
Approx.
timing
Learning
objective
see above
Description
Textbook I5
i, ii and iii
Teacher-led explanation and questioning OR pupils work individually,
in pairs or in small groups through the in-text questions and then
onto the end-of-spread questions if time allows.
Activity I5a Practical
i, ii and iii
How quickly does heat travel? Demo of heat travelling along a bar, 15 min
heating one end, seeing tacks held on by Vaseline or wax falling as it
melts.
✔
✔
Activity I5b Paper
ii and iii
House insulation Pupils explain why insulation in a house works.
15 min
✔
(✔)
Activity I5c
Catalyst Interactive
Presentations 2
iii
Support animation in which pupils identify the good conductors and
insulators in a house.
5 min
20 min
Target group
C
H
E
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R/G
G
R
S
✔
Suggested alternative plenary activities (5–10 minutes)
Review learning
Sharing responses
Group feedback
Word game
Looking ahead
Play ‘Give me three’ with
examples of conductors and
insulators.
In pairs, pupils complete
sentences and compare
their answers with another
group to summarise what
they learnt from Activity
I5a.
In groups, pupils discuss
the answers to Activity I5b.
Word search with conductor,
insulator, then different
examples; after finding
words pupils put them into
two groups.
Demo a spiral above small
Bunsen flame, and ask
pupils to suggest why this
happens.
Learning outcomes
Most pupils will …
Some pupils, making less progress
will …
• recognise when energy transfer is happening
• recognise common situations where heating
by conduction
and/or cooling is happening by conduction
• know that conduction requires the particles of • know that conduction happens best in solids,
the material to be touching
less well in liquids and badly in gases
• appreciate that some solids, e.g. metals, are
• know that some materials are better
good conductors while others, e.g. plastics,
conductors than others.
are insulators
• relate their knowledge of conductors and
insulators to their uses.
Key words
conduction, thermal conductor, thermal insulator, vacuum
Some pupils, making more progress
will …
• also use the particle model of solids, liquids
and gases and energy transfer to explain the
processes of conduction
• also use their understanding of the particle
model to explain why some materials, e.g.
expanded polystyrene, are good insulators.
Out-of-lesson learning
Homework I5
Textbook I5 end-of-spread questions
Activity I5b
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Convection
I6
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Lesson planning
guide
Learning objectives
i
Learn that thermal energy can be transferred by the movement of particles.
ii
Relate this to the movement of particles in solids, liquids and gases.
Scientific enquiry
iii Use models to explain thermal energy transfer by convection. (Framework YTO Sc1 8a)
^ _
Suggested alternative starter activities (5–10 minutes)
UG
Recap last lesson
Share learning
objectives
Problem solving
Capture interest (1)
Capture interest (2)
Play ‘Tell me three things
about Activity I5a from the
last lesson’.
• Find out about convection
in liquids and gases.
• Be able to explain it in
terms of particle theory.
(Sc1)
Show pupils that the
heating element is at the
bottom of a kettle, but the
cooling compartment is at
the top of a fridge.
Demo the candle box to
show how smoke moves in
convection currents.
Show video clips of things
that use convection
currents.
Catalyst Interactive
Presentations 2
Suggested alternative main activities
Activity
Learning
objective
see above
Description
Approx.
timing
Textbook I6
i, ii and iii
Teacher-led explanation and questioning OR pupils work individually,
in pairs or in small groups through the in-text questions and then
onto the end-of-spread questions if time allows.
Activity I6a
Practical
i, ii and iii
Activity I6b
Paper
Activity I6c
Catalyst Interactive
Presentations 2
Target group
C
H
E
S
20 min
R/G
G
R
S
Convection in a liquid Pupils observe convection currents in a
liquid.
15 min
✔
i, ii and iii
Convection currents around us Pupils apply their knowledge of
convection currents to everyday scenarios.
10 min
✔
i, ii and iii
Support animation showing convection currents, particularly sea and
land breezes at day and night time.
5 min
(✔)
✔
✔
✔
Suggested alternative plenary activities (5–10 minutes)
Review learning
Sharing responses
Play ‘Give me three’ and ask Whole-class discussion of
for differences between
Activity I6a.
conduction and convection.
Group feedback
Word game
Looking ahead
In groups, pupils use the
experiments they have seen
to describe what a
convection current is, and
why it happens.
Create a ‘poem’ based on
the word convection.
Wipe a little surgical spirit/
ethanol/water on pupils’
skin, or wet one hand and
direct a cold fan at both
hands and observe the
temperature difference.
Learning outcomes
Most pupils will …
Some pupils, making less progress
will …
• recognise when thermal energy transfer is
happening by conduction
• know that convection requires the particles of
the material to be moving
• know that moving particles set up convection
currents.
• recognise common situation where heating and • also explain convection currents in terms of
cooling happens by convection
expansion and density changes.
• know that convection happens in liquids and
gases but not in solids.
Key words
convection, convection current
Some pupils, making more progress
will …
Out-of-lesson learning
Homework I6
Textbook I6 end-of-spread questions
Activity I6b
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Evaporation, radiation
I7
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Lesson planning
guide
Learning objectives
i
Learn that thermal energy can be transferred by the movement of particles during evaporation.
ii
Learn that thermal energy can be transferred in the absence of particles.
Scientific enquiry
iii Use models to explain thermal energy transfer by evaporation and radiation. (Framework YTO Sc1 8a)
^ _
Suggested alternative starter activities (5–10 minutes)
UG
Recap last lesson
Share learning objectives
Problem solving Capture interest (1)
Capture interest (2)
Ask pupils to give some
examples of heat rising from
the last lesson.
• Find out how heat travels
through space.
• Be able to explain ‘evaporation’
using a particle model. (Sc1)
Discuss with pupils
what is between
us and the Sun
and how heat
energy from the
Sun reaches us.
Show pupils Crooke’s
radiometer and explain why
the vanes move round.
Show two temperature
probes in two equal
volumes of warm water, one
in a narrow container, or
conical flask, one in an
open, flat dish.
Suggested alternative main activities
Activity
Learning
objective
see above
Description
Approx.
timing
Textbook I7
i, ii and iii
Teacher-led explanation and questioning OR Students work
individually, in pairs or in small groups through the in-text questions
and then onto the end-of-spread questions if time allows.
Activity I7a
ICT
i
Activity I7b
Practical
i
Target group
C
H
E
S
20 min
R/G
G
R
S
Cooling by evaporation Pupils use ICT to monitor liquids cooling by
evaporation.
20 min
✔
Radiation Pupils watch a demo of how silver and black surfaces are
affected by radiation.
5 min
Activity I7c
Paper
The vacuum flask Optional demo followed by worksheet on the
thermos flask.
10 min
Activity I7c
Catalyst Interactive
Presentations 2
Support animation of time-lapse pictures of puddle of water
evaporating; then child coming out of swimming pool/sea and
shivering in breeze as water evaporates.
5 min
(✔)
✔
✔
Suggested alternative plenary activities (5–10 minutes)
Review learning
Sharing responses
Group feedback
Word game
Looking back
Wordsearch and definitions
from unit.
Whole-class discussion of
Activity I7a.
In groups, use observations
from Activity I7b to debate
whether heaters should all
be painted black.
Match up the beginnings
and endings of sentences
about evaporation and
radiation.
Pupils revise and
consolidate knowledge from
the unit.
Learning outcomes
Most pupils will …
Some pupils, making less progress
will …
Some pupils, making more progress
will …
• recognise situation where cooling is
occurring by evaporation and relate
this to the difference between the
movement of particles in a liquid and
a gas
• recognise thermal energy transfer by
radiation
• know that radiation does not require
particles.
• recognise common situation where evaporation
causes cooling
• recognise common situations where heating or
cooling is caused by radiation
• know that radiation can happen across empty
space.
• also explain cooling by evaporation in terms of the
loss of the particles carrying the most energy
• also relate infrared radiation to light.
Key words
evaporating/evaporation, radiation, infrared radiation
Out-of-lesson learning
Homework I7
Textbook I7 end-of-spread questions
Activity I7c
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Explaining the results – Think
about variables
I8
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Lesson planning
guide
Learning objectives
i
Think about situations in which two input variables both influence the outcome variable.
The structure of this lesson is based around the CASE approach. The starter activities give concrete preparation. The main activities move away from the
concrete towards a challenging situation, where pupils need to think. The extended plenary gives pupils time to discuss what they have learnt, to
negotiate a method to commit to paper and express their ideas verbally to the rest of the class.
Scientific enquiry
ii
Use models to interpret results (green). (Framework YTO Sc1 8a)
iii Use calculations to process data and make predictions (red). (Framework YTO Sc1 7b, 8d)
Suggested alternative starter activities (5–10 minutes)
Bridging the unit
Setting the context
Show pupils a cup of hot liquid
and ask them to list four ways
that heat energy is lost from the
liquid.
Set up a joulemeter, metal block, heater and
Show pupils a hot drink with a temperature probe
thermometer as described in the textbook. Ask pupils to producing a cooling curve and ask how we could
identify input (independent) variable, outcome
stop it from cooling.
(dependent) variable, what happens to heat from the
heater.
Concrete preparation
Suggested main activities
Activity
Learning
objective
see above
Description
Approx.
timing
Textbook I8
i, ii and iii
Teacher-led explanation and questioning OR pupils work individually,
in pairs or in small groups through the in-text questions and then
onto the end-of-spread questions if time allows.
Activity I8a
Paper
i
What affects how tea cools? Pupils analyse a graph of a cup of tea
cooling and explain what is happening.
Target group
C
H
E
S
30 min
R/G
G
R
S
20 min
✔
(✔)
Suggested alternative plenary activities (5–10 minutes)
Group feedback
Bridging to other topics
Highlight the importance of identifying all the variables in an
investigation and controlling some of them.
Give pupils examples of other things that are affected by more than one
independent variable and ask them to say what the variables are.
Learning outcomes
Most pupils will …
Some pupils, making less progress
will …
Some pupils, making more progress
will …
• interpret data in terms of two input variables
• discuss alternative interpretation of results.
• compare pairs of results to interpret data in
terms of a fair test.
• use their knowledge of temperature and
density to interpret data
• begin to understand compensation – the
interaction of different values of two input
variables to produce the same outcome.
Key words
none
Out-of-lesson learning
Textbook I8 end-of-spread questions
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I
Heating and cooling
Unit map
M
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Temperature and
thermometers
^ _
UG
Temperature
and energy
Evaporation
Radiation
Heating and
cooling
Convection
Expansion and
contraction
Changes of state
Conduction
Copy the unit map and use these words to help you complete it.
You may add words of your own too.
boiling
boiling point
condensing
convection current
cooling
degrees Celsius
freezing
gas
heating
infrared radiation
© Harcourt Education Ltd 2004 Catalyst 2
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liquid
melting
melting point
particles
solid
thermal conductor
thermal energy
thermal insulator
vacuum
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What temperature?
I1
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Starters
Suggested alternative starter activities (5–10 minutes)
p
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Introduce the unit Share learning objectives
Unit map for Heating
and cooling.
^ _
UG LP
Problem solving
• Find out why we need
Use feeling in hands to
thermometers.
decide how hot a bowl of
• Be able to use different kinds water is to demonstrate the
of thermometers. (Sc1)
need for a standard scale.
Capture interest (1)
Capture interest (2)
Show different thermometers,
discuss their uses. Or use
photos.
Catalyst Interactive
Presentations 2
Show video clips of different
scenarios relating to heating
and cooling.
Catalyst Interactive
Presentations 2
Introduce the unit
●
Either draw the outline of the unit map on the board then
ask pupils to give you words to add, saying where to add
them. Suggest some words yourself when necessary to keep
pupils on the right track.
●
Or give out the unit map and ask pupils to work in groups
deciding how to add the listed words to the diagram. Then
go through it on the board as each group gives suggestions.
➔ Unit map
Share learning objectives
●
Ask pupils to write a list of FAQs they would put on a
website telling people about temperature. Collect
suggestions as a whole-class activity, steering pupils
towards those related to the objectives. Conclude by
highlighting the questions you want them to be able to
answer at the end of the lesson.
Problem solving
●
To demonstrate the need for thermometers with a common
scale, set up three bowls of water and ask for two pupil
volunteers. Explain that one bowl contains hot water and
one contains cold water, and the third is an unknown
temperature. Ask one pupil to put a hand in the hot water
while the other puts a hand in the cold water. Time them
for one minute.
●
Then ask them both to plunge their hands in the mystery
bowl and say how it feels. Their answers should conflict
and can be used to show that a hand is not a reliable gauge
of temperature, a thermometer is needed.
Equipment
three bowls of water – one hot at 45 °C,
one cold at 10 °C and one mystery one
at 30 °C
Capture interest (1)
●
Show different thermometers, e.g. liquid crystal for room
temperature or body temperature, maximum and
minimum, clinical, etc., or if these are not available use
photos on Catalyst Interactive Presentations, and ask them to
tell you what thermometers are used for, and to name the
places that they have seen different kinds of thermometers.
➔ Catalyst Interactive Presentations 2
Capture interest (2)
●
●
Show video clips of different scenarios relating to heating
and cooling.
➔ Catalyst Interactive Presentations 2
Ask pupils to write down one thing they see that they have
never seen before or that they don’t understand in terms of
heating and cooling. Explain that they will find the
explanations for these scenarios in the coming unit.
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Temperature and energy
I2
M
Starters
Suggested alternative starter activities (5–10 minutes)
p
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^ _
UG LP
Recap last lesson
Share learning objectives
Pupils work in pairs to • Be able to explain the difference
answer questions on
between thermal energy and temperature.
the pupil sheet about • Carry out an experiment where there are
different types of
two input variables and one output
thermometers.
variable. (Sc1)
Problem solving
Capture interest (1) Capture interest (2)
Pupils suggest whether a
steaming kettle or a bath
is at the highest
temperature and which
has the most heat energy.
Demo the food-burning
experiment with two
different quantities of
water.
Demo of different
amounts of energy being
put into the same
volumes of water.
Recap last lesson
●
Using the pupil sheet, pupils match up types of thermometers
with their use.
➔ Pupil sheet
Share learning objectives
●
Ask pupils to write a list of FAQs they would put on a website
telling people about temperature and energy. Collect
suggestions as a whole-class activity, steering pupils towards
those related to the objectives. Conclude by highlighting the
questions you want them to be able to answer at the end of
the lesson.
Problem solving
●
Pupils work in pairs to discuss the questions on the pupil
sheet (or it could be projected as an OHT).
●
Ask pupils to volunteer answers and lead a discussion to
introduce the idea that temperature and energy are different
things.
➔ Pupil sheet
Capture interest (1)
●
Two pupil volunteers burn similar sized crisps or other food
snack under boiling tubes of water, clamped with
thermometers inside. One is half full and one is nearly full of
water. Note the temperature at the start, ask pupils to predict
the final temperature.
●
Discuss the fact that there are similar amounts of energy but at
the end the water has risen to two different temperatures.
Discuss the variables in the experiment and which one was
controlled.
Equipment
two boiling tubes, crisps, two retort
stands with two clamps on each (one
for thermometer, one for boiling
tube), two thermometers, tongs,
heatproof mats, one Bunsen burner
to set fire to food
Capture interest (2)
●
Demonstrate the heating of two tubes of water with the same
volumes of water; heated with Bunsen burners, one with the
hole open and one with the hole closed. Note the temperature
at the start, ask pupils to predict the final temperature.
Measure the temperature rise in each with thermometers.
●
Discuss the fact that the volumes of water were the same but
different amounts of energy were put in, resulting in different
temperature rises. Discuss the variables in the experiment and
which one was controlled.
© Harcourt Education Ltd 2004 Catalyst 2
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Equipment
two boiling tubes, two clamps, two
thermometers, two Bunsen burners
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I2
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Recap last lesson
?
Match up the thermometers in the left-hand column with places that
u they might be used in the right-hand column.
^ _
UG LP
TN
Temperature and energy
Thermometer
Ordinary laboratory thermometer
(range from – 5 °C to 110 °C)
Clinical thermometer or plastic
thermometer strip
Place it might be used
To measure and record the temperature
of a greenhouse over 24 hours
To measure and record the temperature of
a pottery kiln (several hundred degrees)
High-temperature probe and
datalogger
To measure the boiling point of carbon
dioxide (−78 °C)
Temperature probe and
datalogger
To measure the temperature when salt
water boils (about 105 °C)
Alcohol thermometer (range from
− 80 °C to 100 °C)
To measure the temperature of a person
who is ill
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Temperature and energy
I2
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Starters
Problem solving
p
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^ _
UG LP
TN
●
●
●
●
●
Which of these, bath of water or kettle of water, is likely to be at
the higher temperature?
Which of these contains the most heat energy?
Which would use the most fuel to heat?
Which would cost the most to heat?
Which would take longest to warm up?
Explain your answers.
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
Temperature and energy
I2
Sheet 1 of 1
Starters
Problem solving
●
●
●
●
●
Which of these, bath of water or kettle of water, is likely to be at
the higher temperature?
Which of these contains the most heat energy?
Which would use the most fuel to heat?
Which would cost the most to heat?
Which would take longest to warm up?
Explain your answers.
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Bigger and smaller
I3
M
Starters
Suggested alternative starter activities (5–10 minutes)
p
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^ _
Recap last lesson
Share learning objectives
Brainstorming
Pupils complete the
sentences read out to
them about temperature
and energy.
• Find out what happens when
something is heated or cooled.
• Describe some examples of
heating causing expansion.
• Use the particle model to explain
heating and cooling. (Sc1)
Pupils suggest examples of
times and places where things
expand or contract when the
temperature changes.
UG LP
Problem solving
Demo how a tight screw
cap can be taken off a
bottle.
Capture interest
Demo the heating of
a bimetallic strip.
Recap last lesson
●
Ask pupils to volunteer to complete the sentence read out to the
class, or the whole class does this on individual white boards.
Share learning objectives
●
Questions
Temperature is measured in …
Energy is measured in …
When something is heated the
particles get more …
To measure the heat energy used
I could use a …
To measure the temperature
I could use a …
A big jug of water has more energy
than a small one at the same
temperature because…
Ask pupils to write a list of FAQs they would put on a website
telling people about expansion and contraction. Collect
suggestions as a whole-class activity, steering pupils towards
those related to the objectives. Conclude by highlighting the
questions you want them to be able to answer at the end of the
lesson.
Brainstorming
●
Ask pupils to work in groups and brainstorm some examples
they have come across of things expanding or contracting when
the temperature changes and whether this is useful or a
nuisance.
●
Then ask for groups to suggest some examples to share with the
class and write them up on the board. Explain that they will
discover the reason for expansion and contraction in the lesson.
Examples
liquid in thermometers, hands and
feet swelling in hot weather;
balloons going down when it is
cool; telephone and electric wires
sagging in hot weather; doors
sticking; air inside bike tyres; bottle
tops in hot water
Problem solving
●
Shows pupils a bottle with a screw-on lid, and act as if it is too
tight to undo.
●
Ask pupils for suggestions of methods to open the bottle.
●
Put the top of the bottle into hot water so that the cap expands,
then (with cloth if cap is hot) unscrew it easily.
●
Explain that the metal top expands more than the glass bottle
when it gets hot.
Capture interest
●
Demonstrate holding a bimetallic strip in a Bunsen flame and
ask why it curls. Explain that one metal expands more than the
other.
© Harcourt Education Ltd 2004 Catalyst 2
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Equipment
Bunsen burner, asbestos mat,
bimetallic strip, tongs
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All change
I4
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Suggested alternative starter activities (5–10 minutes)
p
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UG LP
Recap last lesson
Share learning objectives
Play ‘Give me five’. Ask
• Find out what happens to
pupils to give five examples
temperature as things change state.
of things that expand when • Be able to explain what happens
they are heated, or contract
during a change of state using the
when cooled.
particle model. (Sc1)
Problem solving
Show a cooling curve
for gold. Ask pupils
to describe what
information they can
get from the graph.
Capture interest (1)
Capture interest (2)
Show a drink with ice cubes
and a thermometer and ask
for predictions about how
long this drink will stay at
the same temperature.
Pupils are asked for the
opposites of melt and
condense and to explain
the difference between
melt and dissolve.
Recap last lesson
●
Ask pupils for five examples of things that expand when they are heated
or contract when cooled, prompting pupils to be as specific as possible.
Share learning objectives
●
●
●
Display the objectives for pupils, explain what ‘changes of state’ means
and review vocabulary for these changes.
Explain that pupils will see some changes of state in the activities they do.
Remind pupils that they will need to make careful observations and then
be able to use their new knowledge to explain what they saw.
Examples
liquid in thermometer,
metal bar, railway lines,
motorway sections, pipes,
cables, planes when
flying, furniture/houses
during the day, two
metals in a bimetallic
strip
Problem solving
●
●
●
Ask pupils to describe what information they can get from the graph.
They should suggest that – it’s a cooling curve, the substance used is gold,
the experiment lasted 20 minutes, the temperature range was from 800 °C
to 1500 °C.
Then point out that there’s an unexpected flat part in the graph. A few
pupils might suggest that the gold is solidifying – but don’t tell them if no
one thinks of this. Suggest that in the lesson they will look at a substance
cooling and learn why the graph is this shape.
➔ Pupil sheet
Capture interest (1)
●
●
●
Show a ‘drink’ with ice cubes, with thermometer clamped in it – or better,
a probe with temperature displayed – ideally as a graph.
Ask pupils to predict how long the temperature will stay constant. They
can write down their prediction. The experiment can be left running
throughout the lesson; pupils and teacher can check on it occasionally
and pupils can check at the end to see if their prediction was correct.
Although simple theory says the temperature should be 0 °C, it may be
slightly above this. The water next to the ice cube will be at 0 °C, but there
is a temperature gradient to the glass, and from the glass to the air in the
room. Stirring will help. The temperature should remain constant until
the ice has completely melted.
Equipment
beaker full of water and
ice cubes, thermometer
clamped in it, stirring
rod, or datalogger with
temperature probe and
graph displayed
Capture interest (2)
●
●
●
Pupils are asked to give opposites for the following words: melt and
condense (opposite of melt = freeze or solidify, opposite of condense = boil
or evaporate).
Pupils are asked to explain the difference between melt and dissolve.
(Melt is just one substance changing state, dissolve is a solute being mixed
with a solvent.)
Demonstrate dissolving sugar in water, and contrast it with melting sugar
(on a tin lid on a triangle on a tripod over a Bunsen burner).
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All change
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Problem solving
p
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Graph to show temperature of gold metal after
heating to 1500 °C and then allowing it to cool
1500
1450
1400
^ _
UG LP
1350
1300
Temperature (°C)
TN
1250
1200
1150
1100
1050
1000
950
900
850
800
0
2
4
6
8
10
12
14
16
18
20
Time (minutes)
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Conduction
I5
M
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Suggested alternative starter activities (5–10 minutes)
p
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^ _
UG LP
Recap last lesson
Share learning objectives Problem solving
Play ‘It’s on the tip • Find out about conduction.
of my tongue’ with
• Use the particle model to
words for changes of
explain conduction.
state.
• Describe materials as
conductors or insulators.
Show pupils some
examples of saucepans and
ask them to suggest why
they have metal pans and
wooden or plastic handles.
Capture interest (1)
Capture interest (2)
Demo ice trapped by gauze
at the bottom of a test
tube with a Bunsen burner
heating the water at the
top to boiling point.
Volunteer pupils stir sugar into
beakers of very hot water, one with a
plastic spoon and one with a metal
spoon. The class predicts what the
volunteers will feel.
Recap last lesson
●
Play ‘It’s on the tip of my tongue’ by giving definitions and
asking pupils to suggest what word you are trying to say. Either
choose volunteers to answer, or use individual whiteboards to
judge whole class recall of the last lesson.
Share learning objectives
●
●
●
Display the objectives for pupils and ask pupils to describe the
particle arrangements in solids, liquids and gases.
Explain that conduction needs particles to pass on energy. Ask
pupils to suggest in which state things will be the best
conductors and explain why they think that.
Ask pupils what conductors and insulators are to gauge their
prior knowledge from Key Stage 2.
Examples
When something turns from solid
to liquid melting
The opposite of melting freezing
When something turns from gas to
liquid condensing
The temperature when a liquid
turns to a gas boiling point
When a liquid is freezing the
temperature stays constant
Problem solving
●
●
●
Show some examples of saucepans that have metal pans and
wooden or plastic handles.
Ask pupils to suggest why the various materials are used and
what their properties are.
Sum up by saying that in the lesson they will learn how the
particle model can explain these properties.
Equipment
a selection of saucepans with
wooden or plastic handles or
photographs of them (e.g. from
catalogues)
Capture interest (1)
●
●
To demonstrate this, wedge ice in the bottom of a Pyrex test
tube with gauze. Fill it up with water. Heat the top of the water
with a Bunsen burner on a medium flame, holding the test tube
at an angle. (Care! if dry glass is heated it will crack.)
The water at the top boils while the ice is unmelted. This is
because water is a bad conductor, and convection can only carry
heat energy upwards.
Equipment
Pyrex test tube, crushed ice (to fit
in test tube), gauze, Bunsen burner,
test tube holder
Capture interest (2)
●
●
●
●
●
Set up two beakers of very hot water (60–70 °C).
Two volunteers stir one spoonful of sugar into each beaker, one
with a plastic spoon and one with a metal spoon.
Ask the class to predict what the volunteers will feel; the
volunteers report back.
Theory says that metal is a better conductor, so the volunteer
stirring the sugar with the metal teaspoon will feel the spoon
getting hot sooner.
Introduce the terms thermal conductor and thermal insulator.
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
Equipment
two beakers, kettle, plastic and
metal teaspoons, small beaker of
sugar
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Convection
I6
M
6
Starters
Suggested alternative starter activities (5–10 minutes)
p
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t
u
^ _
UG LP
Recap last lesson
Share learning objectives
Problem solving
Play ‘Tell me three
things about Activity
I5a from the last
lesson’.
• Find out about convection in
liquids and gases.
• Be able to explain it in terms
of particle theory. (Sc1)
Show pupils that the heating
Demo the candle box to
element is at the bottom of a kettle, show how smoke moves
but the cooling compartment is at
in convection currents.
the top of a fridge.
Capture interest (1) Capture interest (2)
Show video clips of things
that use convection
currents.
Catalyst Interactive
Presentations 2
Recap last lesson
●
●
Ask pupils to tell you three things about Activity I5a from the last lesson.
Collect three suggestions from one pupil, ask who has anything different
to build up full account on the board.
Share learning objectives
●
●
●
Explain the word fluid (can flow, so can be gas or liquid – need to explain
that a gas can flow).
Remind pupils that gases are bad conductors (and that heat energy cannot
flow downwards in water – if they saw the demonstration in I5).
Remind pupils that scientists need to be able to use scientific theory to
explain observations.
Problem solving
●
●
●
●
●
Show pupils the diagram on the pupil sheet of the heating element at the
bottom of the kettle, and the cooling compartment at the top of the fridge.
To illustrate, if possible, have a real kettle to show.
The pupil sheet asks the question: Why is the heating element at the
bottom of the kettle, but the cooler is at the top of the fridge?
If pupils say ‘because heat goes upwards’, ask them to suggest what they
think is happening in the fridge. If necessary, prompt them by saying that
if hot air rises, maybe cool air falls.
Explain that they will discover the explanation in terms of the particle
model in the lesson.
➔ Pupil sheet
Capture interest (1)
●
●
●
●
Demonstrate the candle box to show how smoke moves in convection
currents.
Explain that the smoke is acting as a marker, to show the path of the air.
First hold the smoking string over the candle chimney, then over the
other chimney, where the smoke will be dragged down the chimney into
the box by the convection current.
Explain that they will carry out an experiment themselves to see this
happening in liquids and discover the explanation in terms of particles in
the lesson.
Capture interest (2)
●
●
●
Show video clips of birds soaring on thermals and hang gliders circling up
and down on thermals.
Ask pupils to suggest how they are rising and falling without flapping
their wings and without engines.
Explain that they will discover the explanation in terms of the particle
model in the lesson.
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
➔ Catalyst Interactive
Presentations 2
➔ Pupil sheet
Equipment
box with glass front and
two glass chimneys,
candle, string (twine), or
wax straws that will burn
with a smoky flame,
matches
➔ Catalyst Interactive
Presentations 2
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I6
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Convection
Starters
Problem solving
p
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cooling
compartment
^ _
UG LP
TN
heating
element
Why is the heating element at the bottom of the kettle, but the
cooler is at the top of the fridge?
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
I6
Convection
Sheet 1 of 1
Starters
Problem solving
cooling
compartment
heating
element
Why is the heating element at the bottom of the kettle, but the
cooler is at the top of the fridge?
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Print Lesson I7 Evaporation, radiation (18 pages)
I6
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Convection
Starters
Capture interest (1)
?
You are going to see two demonstrations to show you how heat
u energy moves in air and water.
^ _
UG LP
TN
candle
B
C
A
D
Draw arrows on the diagram to show which way the smoke
(and air) moves.
© Harcourt Education Ltd 2004 Catalyst 2
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I6
Sheet 1 of 1
Convection
Starters
Capture interest (1)
You are going to see two demonstrations to show you how heat
energy moves in air and water.
candle
B
C
A
D
Draw arrows on the diagram to show which way the smoke
(and air) moves.
© Harcourt Education Ltd 2004 Catalyst 2
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Print Lesson I7 Evaporation, radiation (18 pages)
Evaporation, radiation
I7
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6
Starters
Suggested alternative starter activities (5–10 minutes)
p
?
Recap last lesson
Share learning objectives
Problem solving
Capture interest (1)
Capture interest (2)
t
u
Ask pupils to give some
examples of heat rising
from the last lesson.
• Find out how heat travels
through space.
• Be able to explain
‘evaporation’ using a particle
model. (Sc1)
Discuss with pupils what is
between us and the Sun and
how heat energy from the Sun
reaches us.
Show two temperature probes
in two equal volumes of
warm water, one in a narrow
container, or conical flask,
one in an open, flat dish.
Show pupils Crooke’s
radiometer and explain
why the vanes move
round.
^ _
UG LP
Recap last lesson
●
●
●
Suggest that some people say ‘heat always rises’ and ask pupils to give
some examples from the last lesson that fit that pattern.
Elicit from pupils what they think the situation is with cold air.
Then ask pupils if they think that is always the case and help them refine
the statement to ‘heat rises in liquids and gases’ because convection only
happens in liquids and gases.
Share learning objectives
●
Ask pupils to write a list of FAQs they would put on a website telling
people about evaporation and radiation. Collect suggestions as a
whole-class activity, steering pupils towards those related to the
objectives. Conclude by highlighting the questions you want them to be
able to answer at the end of the lesson.
Problem solving
●
●
●
●
Ask pupils to give the names of the ways that heat can travel and to
describe how these ways work.
Pupils will name conduction and convection, and their descriptions
should show that each needs a material medium.
Ask pupils what is between us and the Sun and elicit the idea that ‘space’
or a ‘vacuum’ means absence of particles.
Conclude that there must be another method for heat transfer since heat
reaches us from the Sun, and explain that they will learn about this in the
lesson.
Capture interest (1)
●
●
●
Set up two temperature probes in two equal volumes of warm water with
equal initial temperature, one in a narrow container or conical flask, one
in an open, flat dish.
Project datalogging graphs to show the temperatures over time.
Ask pupils to suggest why there is a difference in the cooling curves.
Capture interest (2)
●
Show pupils a Crooke’s radiometer (sold as toys: an evacuated bulb,
balanced inside is a mill with vanes that have white and black sides).
●
In sunlight the mill spins fast. The reason is that the black surface
absorbs more heat energy, it warms up the gas on that side of the vane,
the gas particles move faster on the black side, they hit the vane and
make it spin.
© Harcourt Education Ltd 2004 Catalyst 2
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Equipment
two containers of warm
water (one in a conical
flask, one in a wide, flat
dish), two temperature
probes and datalogging
equipment
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Print Lesson I7 Evaporation, radiation (18 pages)
Explaining the results – Think
about
I8
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6
Starters
p
?
Suggested alternative starter activities (5–10 minutes)
t
u
Bridging to the unit
Setting the context
Show pupils a cup of hot liquid and
ask them to list four ways that heat
energy is lost from the liquid.
Set up a joulemeter, metal block, heater and thermometer Show pupils a hot drink with a temperature
as described in the textbook. Ask pupils to identify input probe producing a cooling curve and ask how we
(independent) variable, outcome (dependent) variable,
could stop it from cooling.
what happens to heat from the heater.
^ _
UG LP
Concrete preparation
Bridging to the unit
●
Show pupils a cup of a hot drink and ask them to list the four
ways the drink loses heat energy.
●
Pupils respond (hopefully) with conduction, convection,
radiation and evaporation.
●
If pupils say where the heat is lost, e.g. through the sides, then
prompt them to give the name, e.g. ‘What do we call it when
heat travels through a solid like the side of the cup?’
Setting the context
●
Set up a metal block, heater, joulemeter and thermometer.
●
Ask pupils to identify the independent variables and what we
can do to control each one. (Type of metal, mass of block,
insulation or not around block, power of heater, time that
experiment runs for.)
●
Ask pupils to identify the dependent variable (temperature).
Equipment
metal block, heater, joulemeter,
thermometer, heatproof mat, power
supply for heater
Concrete preparation
●
Set up a large mug of hot liquid with a temperature probe inside
it, and a cooling curve displayed on screen.
●
Ask pupils to suggest what shape the graph will be if the liquid
cools more slowly or more quickly.
●
Then ask pupils what we could change so that the graph goes
down faster/more slowly.
●
Remind pupils that these ideas are independent or input
variables.
© Harcourt Education Ltd 2004 Catalyst 2
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Answers
lid/no lid, amount of liquid,
starting temperature, room
temperature, size of mug, material
of mug, wrapping around mug,
colour of mug
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Print Lesson I7 Evaporation, radiation (18 pages)
Making a thermometer
I1a
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t
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^ _
UG LP
6
Teacher
activity notes
Type
Purpose
Differentiation
Practical
Pupils make a simple water thermometer and observe expansion and contraction of
liquid as the temperature changes.
Core, Extension
Running the activity
Pupils work in pairs to produce a simple water thermometer, calibrate it and use it
to measure some different temperatures.
Core: Full instructions are given on the sheet.
TC Extension: Pupils design their own thermometers from equipment provided.
Expected outcomes
Pupils discover that the water appears to move up the tube as it gets hotter and
down the tube as it gets colder. They should link this to expansion and
contraction of the water.
Pitfalls
Pupils may need assistance in getting the initial level of the water correct. It needs
to be about halfway up the glass tube.
Calibrating to 0 °C using iced water will, of course, not be very accurate because
water expands as it cools between + 4 ° and 0 °C.
Safety notes
Take care pupils do not break the thin glass tubes.
Answers
Core:
1 Moved down the tube.
2 Moved up the tube.
3 Depends on results (should be around 37 °C).
4 Pupils should describe the process similar to step 6 on the Core sheet.
5 Test it at different temperatures with a clinical thermometer or a digital
thermometer to see if you get the same answers.
Extension:
1 Colder – level went down; hotter – level went up.
2 Depends on results (should be around 37 °C).
3 Test it at different temperatures with a clinical thermometer or a digital
thermometer to see if you get the same answers.
4 Depends on the thermometer.
5 Water would evaporate out of the tube, making the thermometer inaccurate.
6 The liquid level moves faster, they are more accurately calibrated, they stay
accurate with time, the liquid in them freezes at a lower temperature and boils
at a higher temperature so they can be used over a wider range of temperatures.
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Print Lesson I7 Evaporation, radiation (18 pages)
p
?
t
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^ _
Technician
activity notes
Making a thermometer
I1a
M
6
Type
Purpose
Differentiation
Practical
Pupils make a simple water thermometer and observe expansion and contraction of
liquid as the temperature changes.
Core, Extension
Equipment
50°C
For each pair:
UG LP
●
TN
●
●
●
●
●
●
●
boiling tube
boiling tube rack
bung with 10 cm glass tube
access to water bath at 50 °C
beaker of iced water
two sticky labels
coloured water (food dye will do)
marker pen (waterproof)
0 °C
For your information
Running the activity
Pupils work in pairs to produce a simple water thermometer, calibrate it
and use it to measure some different temperatures.
Core: Full instructions are given on the sheet.
Extension: Pupils design their own thermometers from equipment provided.
Expected outcomes
Pupils discover that the water appears to move up the tube as it gets hotter and
down the tube as it gets colder. They should link this to expansion and
contraction of the water.
Pitfalls
Pupils may need assistance in getting the initial level of the water correct. It needs
to be about halfway up the glass tube.
Calibrating to 0 °C using iced water will, of course, not be very accurate because
water expands as it cools between + 4 ° and 0 °C.
Safety notes
Take care pupils do not break the thin glass tubes.
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Print Lesson I7 Evaporation, radiation (18 pages)
Making a thermometer
I1a
M
p
t
6
Activity
Core
W A thermometer is made from a very thin tube of glass filled with
a liquid like mercury. In this activity you are going to make a very
?
simple water thermometer.
u
^ _
UG LP
TN TC
Equipment
●
●
●
●
boiling tube
boiling tube rack
water bath at 50ºC
marker pen
Take care
not to
break the
thin glass tubing.
50°C
●
●
●
●
bung with glass tube
coloured water
beaker of iced water
sticky labels
0 °C
Obtaining evidence
1 Fill the boiling tube almost to the top with the coloured water.
2 Fit the bung and glass tube into the boiling tube as shown. If the
water comes out of the top of the glass tube, take the bung off,
tip some water out and try again.
3 Adjust the water level so it is about halfway up the glass tube.
4 Place the boiling tube into the beaker of iced water. When the
water in the glass tube stops moving, mark this new water level 0ºC.
5 Place the boiling tube in the water bath. When the water in the glass tube
stops moving, mark this new water level 50ºC.
6 Measure the distance between the 0ºC and the 50ºC marks. Divide this
distance by 10. Use your answer to mark 5ºC intervals along your
thermometer (i.e. 5ºC, 10ºC, 15ºC and so on up to 45ºC). You have now
calibrated your thermometer.
7 Hold the boiling tube tightly between both your hands. When the water in
the glass tube stops moving, measure the water level against the marks on
your thermometer. Record the temperature.
8 Take further measurements, such as:
●
on a sunny windowsill or above a radiator
●
in a cool cupboard or outside on a cold day.
9 Make a table to record your results.
Considering the evidence
1
2
3
4
How did the water level change when your thermometer got cold?
How did the water level change when your thermometer got hot?
From your results, what is your body temperature?
Describe the method for putting a scale on your thermometer.
Evaluating
5 How accurate do you think your water thermometer is? How could you
test this?
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Print Lesson I7 Evaporation, radiation (18 pages)
p
t
Activity
Extension
Making a thermometer
I1a
M
6
W A thermometer is made from a very thin tube of glass filled with
a liquid like mercury. In this activity you are going to make a very
?
simple water thermometer.
u
50°C
^ _
UG LP
Equipment
●
●
TN TC
Take care
not to
break the
thin glass tubing.
●
●
●
●
●
●
boiling tube
boiling tube rack
water bath at 50ºC
marker pen
bung with glass tube
coloured water
beaker of iced water
sticky labels
0 °C
Obtaining evidence
1 Using the equipment available, design a water thermometer that
will measure temperatures between 0ºC and 50ºC.
2 Calibrate your thermometer in 5ºC intervals.
3 Use your thermometer to record various temperatures, for
example:
●
your body (hold the thermometer in your hands)
●
a sunny windowsill
●
a cool cupboard
●
in the main part of the fridge.
Considering the evidence
1 What happened to the water level as your thermometer got
hotter and colder?
2 From your results, what is your body temperature?
Evaluating
3 How accurate is your thermometer? How could you test this?
4 How quickly does your thermometer reach the new temperature
when you move it to a different place?
5 What would happen if you left your thermometer for a few days?
6 What are the advantages of the liquid-filled thermometers you
use in school?
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Print Lesson I7 Evaporation, radiation (18 pages)
Energy and temperature
I2a
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t
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^ _
UG LP
TC
Teacher
activity notes
Type
Purpose
Differentiation
Practical
To show pupils that different amounts of energy can cause the same rise in temperature, Core, Help, Extension
i.e. that temperature and energy are related but not the same.
Running the activity
Pupils heat different volumes of water electrically so that the temperature rises by 10 °C. They
measure the amount of energy needed using a joulemeter. The activity sheet directs the pupils
to find out how the joulemeter works before starting the experiment. This is because
joulemeters vary greatly. Electrical heaters also vary. Try to select beakers or other containers
that ensure that the bulk of the heater is under water.
Core: Pupils follow the instructions on the sheet.
Help: Pupils record their measurements and answers on the sheet.
Extension: The sheet leads pupils through calculating energy efficiency.
Other relevant material
Skill sheet 16: Energy transfer diagrams
Expected outcomes
More energy will be needed to raise the temperature of larger volumes of water. Theoretically,
twice the volume of water should require twice the energy, but energy losses to the
surroundings may be different if different amounts of the heater are under water.
Pitfalls
Ensure that the pupils understand how to use the joulemeter. Make sure that they set the power
packs to the correct voltage for the heater. Make sure that the heater will not overbalance the
beaker. Clamp it if necessary.
Safety notes
Warn pupils that the heater will become very hot. Have a heatproof mat on which to rest the
heater when not in use. Turn off the power supply between experiments. Warn against
handling switches and sockets with wet hands.
Answers
Core:
1 – (thermal energy)→ water –(thermal energy)→ thermometer 2 Depends on individual
results. 3 There are more particles in 200 cm3 of water than 100 cm3 of water, so more energy
is needed to increase the kinetic energy of all the particles. 4 The average energy per particle
was increased by the same amount, so the same temperature rise occurred, but there were more
particles in 200 cm3 water than in 100 cm3 water, so more energy was needed.
Help:
1 – (thermal energy)→ water –(thermal energy)→ thermometer
results. 3 Particles, 200, 100, energy, 200, temperature.
2 Depends on individual
Extension:
1 Pupils should predict that 200 cm3 takes more energy because it contains more particles.
2 See Core question 1. 4 – 5 See Core questions 3 and 4. 6 Pupils should find it takes
approximately double the energy but may identify that some heat is transferred to the
surroundings. 7 a 4.2 × 100 = 420 J b 4.2 × 100 × 10 = 4200 J 8 4200 × 2 = 8400 J
9 Answer should be no; some energy is lost to the surroundings, but this will depend on pupil
data. 10 Some of the energy is lost to the surroundings.
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Print Lesson I7 Evaporation, radiation (18 pages)
Energy and temperature
I2a
M
p
?
t
u
^ _
UG LP
TN
6
Technician
activity notes
Type
Purpose
Differentiation
Practical
To show pupils that different amounts of energy can cause the same rise in temperature, Core, Help, Extension
i.e. that temperature and energy are related but not the same.
Other relevant material
Skill sheet 16: Energy transfer diagrams
Equipment
For each group:
●
●
●
●
●
●
●
●
●
joulemeter
power supply
heating element
three leads
thermometer
two clamp stands with clamps and bosses
250 cm3 beaker
150 cm3 beaker
100 cm3 measuring cylinder
For your information
Running the activity
Pupils heat different volumes of water electrically so that the temperature rises by
10 °C. They measure the amount of energy needed using a joulemeter. The activity
sheet directs the pupils to find out how the joulemeter works before starting the
experiment. This is because joulemeters vary greatly. Electrical heaters also vary.
Try to select beakers or other containers that ensure that the bulk of the heater is
under water.
Core: Pupils follow the instructions on the sheet.
Help: Pupils record their measurements and answers on the sheet.
Extension: The sheet leads pupils through calculating energy efficiency.
Expected outcomes
More energy will be needed to raise the temperature of larger volumes of water.
Theoretically, twice the volume of water should require twice the energy, but
energy losses to the surroundings may be different if different amounts of the
heater are under water.
Pitfalls
Ensure that the pupils understand how to use the joulemeter. Make sure that they
set the power packs to the correct voltage for the heater. Make sure that the heater
will not overbalance the beaker. Clamp it if necessary.
Safety notes
Warn pupils that the heater will become very hot. Have a heatproof mat on which
to rest the heater when not in use. Turn off the power supply between
experiments. Warn pupils not to handle switches and sockets with wet hands.
© Harcourt Education Ltd 2004 Catalyst 2
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Print Lesson I7 Evaporation, radiation (18 pages)
I2a
M
p
t
Activity
Core
Energy and temperature
W You are going to find out how much energy is needed to heat
100cm3 and 200cm3 of water by 10°C.
?
Make sure you know how to use the joulemeter to measure the
u
amount of energy needed to heat the water.
Wear eye
protection.
Do not handle
electrical switches
with wet hands.
The heater gets very hot.
Put it on a heatproof mat
between experiments and
don’t touch the hot part.
^ _
Make sure that the power supply is set on the correct voltage for
UG LP your heater to heat the water.
TN TC
Switch off the power supply
between experiments.
Obtaining evidence
thermometer
1 Set up the apparatus as shown in
the diagram.
2 Measure 100cm3 of water into the
beaker.
3 Record the temperature.
4 Heat by 10°C. Stir the water all the time.
Record the temperature and the energy
transferred using the joulemeter.
5 Repeat with 200cm3 water.
heater
joulemeter
–
water
+
power supply
Considering the evidence
1 Copy and complete this energy transfer diagram to show how the
thermometer measures temperature.
.......................
.......................
water
thermometer
energy
energy
2 How much energy was needed to heat:
a 100cm3 water by 10°C
b 200cm3 water by 10°C?
3 Why was more energy needed to heat 200cm3 than 100cm3 of water?
4 Use the particle theory to explain why the same temperature change was
recorded, but different amounts of energy were transferred.
© Harcourt Education Ltd 2004 Catalyst 2
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Print Lesson I7 Evaporation, radiation (18 pages)
I2a
M
p
t
^
UG
Activity
Help
Energy and temperature
W You are going to find out how much energy is needed to heat
100cm3 and 200cm3 of water by 10°C.
?
Do you know how to use the joulemeter? If not, ask your teacher.
u
_ Do you know the correct voltage for your heater? If not, ask your
teacher.
LP
TN TC
Wear eye
protection.
Do not handle
electrical switches
with wet hands.
The heater gets very hot.
Put it on a heatproof mat
between experiments and
don’t touch the hot part.
Switch off the power supply
between experiments.
Obtaining evidence
1 Set up the apparatus as shown in the diagram.
2 Ask your teacher to check your apparatus.
3 Measure 100cm3 of water into the beaker. Use a measuring cylinder.
thermometer
heater
joulemeter
–
water
+
power supply
4 Record the temperature in the table.
Volume of water
100cm3
200cm3
Start temperature in °C
End temperature in °C
Energy transferred in J
5 Work out the end temperature. This is the starting temperature + 10°C.
Write the end temperature in the table.
6 Heat by 10°C. Stir the water all the time. Write down the energy
transferred.
7 Repeat with 200cm3 water.
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6
Print Lesson I7 Evaporation, radiation (18 pages)
I2a
Activity
Help
Energy and temperature (continued)
M
W
Considering the evidence
p
?
1 Complete this energy transfer diagram to show how the
t
u
^ _
UG LP
TN TC
thermometer measures the temperature.
.......................
.......................
water
thermometer
energy
energy
2 How much energy was needed to heat:
a 100cm3 water by 10°C?
J
b 200cm3 water by 10°C?
J
3 Complete this conclusion using the words below. You can use
the words more than once.
temperature
particles
There are more
energy
200
100
cm3 of water
in
cm3 of water.
than in
This means that more
was needed to heat
cm3 water to get a 10°C
© Harcourt Education Ltd 2004 Catalyst 2
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rise.
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Print Lesson I7 Evaporation, radiation (18 pages)
p
t
Activity
Extension
Energy and temperature
I2a
M
6
W You are going to find out how much energy is needed to heat
100cm3 and 200cm3 of water by 10°C.
?
Make sure you know how to use the joulemeter to measure the
u amount of energy needed to heat the water.
Wear eye
protection.
Do not handle
electrical switches
with wet hands.
UG LP your heater to heat the water.
The heater gets very hot.
Put it on a heatproof mat
between experiments and
don’t touch the hot part.
TN TC
Switch off the power supply
between experiments.
^ _ Make sure that the power supply is set on the correct voltage for
Predicting
1 Write down what you expect the results to show, and give a reason for
your prediction.
Obtaining evidence
thermometer
1 Set up the apparatus as shown in the
diagram.
2 Measure 100cm3 of water into the beaker.
3 Record the temperature.
4 Heat by 10°C. Stir the water all the time.
Record the temperature and the energy
transferred using the joulemeter.
5 Repeat with 200cm3 water.
heater
joulemeter
–
water
+
power supply
Considering the evidence
2 Draw an energy transfer diagram to describe how the water was
3
4
5
6
heated and how the thermometer measures temperature.
How much energy was needed to heat:
a 100cm3 water by 10°C
b 200cm3 water by 10°C?
Why was more energy needed to heat 200cm3 than 100cm3 of water?
Explain why the same temperature change was recorded, but different
amounts of energy were transferred.
Are your results what you expected? If not, suggest why not.
If all the energy goes into the water, it takes 4.2J to raise the temperature
of 1cm3 water by 1°C.
7 If all the energy had gone into the water, how much energy should
have been needed to raise 100cm3 of water by: a 1°C b 10°C?
8 If all the energy had gone into the water, how much energy should
have been needed to raise 200cm3 of water by 10°C?
9 Did all the energy go into the water? Explain your answer.
10 Suggest where the rest of the energy ended up.
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Print Lesson I7 Evaporation, radiation (18 pages)
p
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t
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Teacher
activity notes
Expansion in solids
I3a
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6
Type
Purpose
Differentiation
Practical
Demonstrate expansion and contraction while pupils observe and complete an activity
sheet.
Core
Running the activity
The teacher demonstrates the experiments. Pupils complete the sheets as they watch.
UG LP The ball and ring: Show that the ball will fit through the ring, but when the ball is
heated in a Bunsen flame it will not fit because it has expanded. If the ring is then
TC heated as well it too expands, so the ball will fit through. If both are put in cold water
they will both contract, so the ball will fit through the ring.
The metal rod: Set up the experiment as shown on the sheet, with the metal rod resting
gently on the pin with the paper flag. Heat the metal rod carefully by holding a
Bunsen over it. (Taking care not to set the paper flag on fire!) As the rod expands it
will roll the pin, and the flag will turn.
Other relevant material
If the equipment is available, the breaking bar
experiment could also be demonstrated here. As the
long metal bar is heated the screw is tightened.
When it cools, the long metal bar contracts, breaking
the cast iron bar.
cast iron bar fits
through hole
heat
screw tightened
as bar is heated
Expected outcomes
Pupils understand the principles behind expansion and
contraction in solids, in terms of particles moving
apart and closer together.
long metal bar strong metal holder
Pitfalls
Movement of the paper flag can be difficult to observe, especially from a distance.
Safety notes
Do not let pupils handle hot metal objects.
Use tongs or a heatproof glove to hold the hot chain.
Do not set fire to the paper flag.
Use a safety screen (and goggles for the teacher) for the breaking bar demonstration.
Answers
1 yes 2 no 3 The ball has been heated. Its particles vibrate more and take up
more space. The ball expands. 4 The ball fits through again. 5 The ring has been
heated. Its particles vibrate more and take up more space. The ring expands and the
ball can fit through. 6 yes 7 The ball and ring have been cooled down. Their
particles vibrate less and take up less space. They both contract. 8 The flag rotates.
9 The flag rotates because the pin is rotating, so the rod must be expanding and
rolling the pin along the bench. 10 The rod has been heated. Its particles vibrate
more and take up more space. The rod expands, rolling the pin. 11 The flag will
move back to where it started because the rod will cool and contract.
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TN
Technician
activity notes
Expansion in solids
I3a
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6
Type
Purpose
Differentiation
Practical
Demonstrate expansion and contraction while pupils observe and complete an activity
sheet.
Core
Other relevant material
If the equipment is available, the breaking bar experiment could also be demonstrated here. As the long metal
bar is heated the screw is tightened. When it cools, the long metal bar contracts, breaking the cast iron bar.
Equipment
For teacher demonstrations:
●
●
●
●
●
●
●
cast iron bar fits
through hole
heat
screw tightened
as bar is heated
metal ball and ring
Bunsen burner
tongs or heatproof glove
heatproof mat
metal rod at least 30 cm long
stand and clamp
metal pin with paper flag attached
long metal bar strong metal holder
For your information
Running the activity
The teacher demonstrates the experiments. Pupils complete the sheets as they watch.
The ball and ring: Show that the ball will fit through the ring, but when the ball is heated in a Bunsen flame
it will not fit because it has expanded. If the ring is then heated as well it too expands, so the ball will fit
through. If both are put in cold water they will both contract, so the ball will fit through the ring.
The metal rod: Set up the experiment as shown on the sheet, with the metal rod resting gently on the pin
with the paper flag. Heat the metal rod carefully by holding a Bunsen over it. (Taking care not to set the
paper flag on fire!) As the rod expands it will roll the pin, and the flag will turn.
Expected outcomes
Pupils understand the principles behind expansion and contraction in solids, in terms of particles moving
apart and closer together.
Pitfalls
Movement of the paper flag can be difficult to observe, especially from a distance.
Safety notes
Do not let pupils handle hot metal objects.
Use tongs or a heatproof glove to hold the hot chain.
Do not set fire to the paper flag.
Use a safety screen (and goggles for the teacher) for the breaking bar demonstration.
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p
t
Activity
Core
Expansion in solids
I3a
M
6
W When a solid is heated it expands. Your teacher will demonstrate
some experiments to show this. Observe these experiments
?
closely and answer these questions.
u
^ _
Even when
metals look
cold they
may still be very hot.
Experiment 1: The ball and ring
UG LP 1 Observe the ball and ring.
TN TC
1 Can the ball fit through the ring?
2 The ball is now heated in a Bunsen flame.
2 Can the ball fit through the ring now?
3 Explain why this happens. Use the word ‘particles’
in your answer.
3 The ring is now heated in a Bunsen flame.
4 Describe what happens.
5 Explain why this happens. Use the word ‘particles’ in your
answer.
4 The ball and ring are both put into cold water.
6 Can the ball fit through the ring?
7 Explain why this happens. Use the word ‘particles’ in your
answer.
Experiment 2: The metal rod
metal rod
5 The metal rod is held firmly at one end. The
rod is heated up. Observe the rod carefully.
8 What happens to the flag on the pin?
9 What does this show?
10
11
paper flag
on pin
Explain why this happens. Use the word
‘particles’ in your answer.
What do you think will happen to the flag
as the rod cools down? Explain your answer.
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Expansion in gases
I3b
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UG LP
6
Teacher
activity notes
Type
Purpose
Differentiation
Practical
Demonstration that air expands and contracts with temperature.
Core
Running the activity
Set up the flask and capillary tube as described in the Technician activity notes.
Place the flask in different temperatures of water and measure the level of the air
column against the scale on the ruler.
Pupils record the results in a table, plot a graph and answer questions about what
TC they have observed.
Expected outcomes
Pupils should discover a relationship between temperature and volume.
Safety notes
The capillary tube is fragile – handle with care.
ICT opportunities
A spreadsheet can be used to produce a graph of the results.
Answers
1 Depends on results.
2 Depends on results.
3 Volume increases with temperature.
4 As the temperature increases, the air particles move further apart from each
other.
5 a Diagram shows particles further apart.
b Diagram shows particles closer together.
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UG LP
TN
Technician
activity notes
Expansion in gases
I3b
M
6
Type
Purpose
Differentiation
Practical
Demonstration that air expands and contracts with temperature.
Core
Equipment
For teacher demonstration:
●
●
●
●
●
●
●
●
●
●
round-bottomed flask
bung with 50 cm capillary tube
30 cm ruler
sticky tape
stand and clamp
large beaker
coloured water (food dye will do)
kettle
ice
thermometer
When setting up the apparatus, first suck up a small amount of coloured liquid to
seal the capillary tube about halfway up its length. Pupils will measure the bottom
end of this ‘slug’ of coloured water against the scale on the ruler.
For your information
Running the activity
Set up the flask and capillary tube as described above. Place the
flask in water at different temperatures and measure the level of
the air column against the scale on the ruler.
Pupils record the results in a table, plot a graph and answer
questions about what they have observed.
Expected outcomes
Pupils should discover a relationship between temperature and
volume.
measure
this point
slug of
coloured water
column of air
ruler attached to
capillary tube
flask of air
Safety notes
The capillary tube is fragile – handle with care.
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UG
Activity
Core
Expansion in gases
W In this experiment you are going to observe what
happens to the size of a column of air at different
?
temperatures.
u
Your teacher will demonstrate this experiment to you.
_ The slug of water will move as the air inside the flask
LP expands and contracts.
measure
this point
slug of
coloured water
column of air
ruler attached to
capillary tube
TN TC Your teacher will measure the height of the bottom of
the slug of water as the flask is placed in water at
different temperatures.
flask of air
1 Copy and complete this table.
Height of water in mm
2 Use the results in your table to draw a line graph of
height of water against temperature. The height of
the water slug shows how the volume of air in the
flask changes.
1 At what temperature is the volume of air the
smallest?
2 At what temperature is the volume of air the biggest?
3 What conclusions can you make about the
relationship between the volume of the air and the
temperature?
4 Explain why there is this relationship.
Height of water slug in mm
Temperature in °C
Temperature in °C
3 The diagram on the right shows the molecules of air inside the
capillary tube at 50ºC.
5 Draw a similar diagram to show the molecules of air inside the
capillary tube at:
a 75ºC
b 25ºC
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Expansion in liquids
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6
Teacher
activity notes
Type
Purpose
Differentiation
Paper
Demonstration that air expands and contracts with temperature.
Extension
Running the activity
This is a paper activity for more able pupils, who have to record information from
the sheet and answer questions.
Expected outcomes
Pupils understand that different liquids expand and contract by different amounts,
but water does not behave as you would expect – its particles do not fit together
compactly as it freezes, but form crystals which are less dense than water.
Answers
1 They vibrate more and spread out.
2 Glycerol, oil, water, paraffin.
3 4 °C
4 The particles vibrate less and fit closer together.
5 Instead of forming a close-fitting solid, the water particles form crystals which
fit together in a non-compact way, forming ice which is less dense than water.
6 It is above freezing point.
7 The water at the bottom is not frozen so they will not freeze either.
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Activity
Extension
Expansion in liquids
W Different liquids expand and
contract by different amounts. You
?
are going to investigate expansion
u of some liquids, and see how water
behaves differently.
50
40
30
20
10
0
^ _
all started
at this level
UG LP All of these glass bottles are the same
size. They were all filled to the same
TN
mark at the start of the experiment.
When hot water was added to the
trough, the liquid levels in the tubes
changed.
hot water
1
2
3
4
water
oil
paraffin
glycerol
1 Use the scale shown to measure how much each liquid rose. Record this in a table.
1 Explain what happened to the particles in the liquids.
2 List the four liquids in order of increasing amount of expansion.
Water contracts as it gets colder
down to a temperature of 4°C.
From 4ºC down to 0°C it expands.
Ice crystals start forming at +4°C.
The crystals fit together in a
non-compact way with space
between them. So, even though ice
is a solid, it is less dense than liquid
water. This means that ice floats on
top of water.
3 Here are four bottles of water at
different temperatures. At what
temperature is the water the most dense?
4 Explain why liquids contract as they get colder.
5 Explain why below 4ºC water does not behave as you would have expected.
2 Look at this diagram of a fish pond.
6 What does this tell you about the
ice 0 °C
temperature of the water below the
ice?
7 How do fish survive at the bottom of
frozen ponds in winter?
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Changes of state
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6
Teacher
activity notes
Type
Purpose
Differentiation
ICT
Pupils use temperature probe and datalogger to produce a cooling curve for stearic acid.
Core, Help, Extension
Running the activity
Pupils work in small groups, or the activity could be carried out as a teacher demonstration. If limited
datalogging apparatus is available then the experiment may be done as part of a circus of experiments. It is
also possible to carry out the activity using thermometers.
Core: The method is given and the pupils follow the instructions to produce their own graphs. Questions
TC help them analyse the graph. They are asked to explain what is happening in terms of particles.
Help: The sheet provides a set of axes for pupils to record their results. More structured questions lead them
to their conclusions. Instructions for the experiment are not given on this sheet, so pupils will need help
with the activity (instructions on the Core sheet), or the Help sheet can be used to accompany a teacher
demonstration.
Extension: Pupils predict what they think will happen, then plan and carry out their own full investigation.
Other relevant material
IT Activities for Science 11–14 (Heinemann): Datalogging guides (p.165–7); spreadsheets ‘Melting moments’
(p. 18–19) and ‘From ice to steam’ (p. 25–6).
Extension pupils could use the writing frames on:
Skill sheet 20: Writing frame: Planning an investigation
Skill sheet 21: Writing frame: Reporting an investigation
Expected outcomes
The graph produced by the cooling stearic acid should show a plateau. From this, pupils should be able to
determine the melting point of the stearic acid.
Pitfalls
The timescale of the experiment should be at least 20 minutes. The stearic acid will need to be re-melted to
allow for the removal of the temperature probes at the end of the experiment.
Safety notes
Stearic acid can be harmful. Wash hands after use. Take care with hot water. If scalded with hot stearic acid
or water, hold the affected part under cold running water.
Answers
Core:
1 Goes down steadily, levels out, then goes down again. 2 Depends on graph/ stearic acid used.
3 Depends on graph/ stearic acid used. 4 Particles of the liquid stearic acid are losing energy, they move
more slowly, forces of attraction form, they become particles of a solid.
Help:
1 No (levelled out for a bit). 2 Depends on graph/ stearic acid.
4 Liquid, solid, temperature, slowly, join, melting.
3 Depends on graph/ stearic acid.
Extension:
1 It will stay constant. 2 Energy is being released and used to make forces of attraction between the
molecules. 3 Goes down steadily, levels out, then goes down again. 4 Depends on graph/ stearic acid.
5 Depends on graph/ stearic acid. 6 Particles of the liquid stearic acid are losing energy, they move more
slowly, forces of attraction form, they become particles of a solid. 7 a Any valid method. b Datalogger –
many more readings taken, easier to read than a thermometer to a greater level of accuracy. 8 Any valid
method involving re-melting the stearic acid and recording the temperature as it melts.
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Changes of state
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6
Technician
activity notes
Type
Purpose
Differentiation
ICT
Pupils use temperature probe and datalogger to produce a cooling curve for stearic acid.
Core, Help, Extension
Other relevant material
IT Activities for Science 11–14 (Heinemann): Datalogging guides (p.165–7);
spreadsheets ‘Melting moments’ (p.18–19) and ‘From ice to steam’ (p.25–6).
UG LP Extension pupils could use the writing frames on:
TN
Skill sheet 20: Writing frame: Planning an investigation
Skill sheet 21: Writing frame: Reporting an investigation
Equipment needed
For each group (or teacher demonstration):
●
●
●
●
●
●
●
●
Bunsen burner
boiling tube of stearic acid (or wax)
clamp stand
tripod and gauze
beaker of water
datalogger
temperature probe
computer and interface
For your information
Running the activity
Pupils work in small groups, or the activity could be carried out as a teacher
demonstration. If limited datalogging apparatus is available then the experiment
may be done as part of a circus of experiments. It is also possible to carry out the
activity using thermometers.
Core: The method is given and the pupils follow the instructions to produce their
own graphs. Questions help them analyse the graph. They are asked to explain
what is happening in terms of particles.
Help: The sheet provides a set of axes for pupils to record their results. More
structured questions lead them to their conclusions. Instructions for the
experiment are not given on this sheet, so pupils will need help with the activity
(instructions on the Core sheet), or the Help sheet can be used to accompany a
teacher demonstration.
Extension: Pupils predict what they think will happen, then plan and carry out
their own full investigation.
Expected outcomes
The graph produced by the cooling stearic acid should show a plateau. From this,
pupils should be able to determine the melting point of the stearic acid.
Pitfalls
The timescale of the experiment should be at least 20 minutes. The stearic acid
will need to be re-melted to allow for the removal of the temperature probes at the
end of the experiment.
Safety notes
Stearic acid can be harmful. Wash hands after use. Take care with hot water. If
scalded with hot stearic acid or water, hold the affected part under cold running
water.
© Harcourt Education Ltd 2004 Catalyst 2
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Changes of state
I4a
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Activity
Core
W As a liquid cools, its particles move more slowly and it turns
into a solid. You are going to look at the cooling curve for
?
stearic acid as it changes state.
u
^ _
UG LP
TN TC
Equipment
●
●
●
●
●
●
●
●
Bunsen burner
boiling tube of stearic acid
beaker of water
clamp stand
tripod and gauze
temperature probe
computer and interface
datalogging software
Wear eye
protection.
Take care with
hot water and
hot stearic acid.
Do not remove the
temperature probe from
solid stearic acid.
boiling tube
Wash your hands, stearic
acid can be harmful.
water
tripod
Bunsen burner
Obtaining evidence
1 Set up the computer and run the
datalogging software.
2 Set the timespan of the experiment
to 20 minutes.
3 Place the boiling tube of stearic acid in
the beaker of water and heat it until
the stearic acid melts. Remove it from
the beaker still attached to the stand
and clamp.
4 Put the temperature probe into the
stearic acid.
5 Remove the boiling tube from the hot
water and put it in the rack.
6 Start recording.
7 Once the stearic acid is totally solid, stop recording.
interface
temperature probe
in molten stearic acid
computer
Presenting the results
The computer will draw a graph of temperature against time.
8 Print out the graph, or draw a sketch of it.
Considering the evidence
1
2
3
4
Describe the shape of the graph.
At what point did the temperature stop falling?
Use the graph to work out the melting point of the stearic acid.
Explain what is happening to the stearic acid particles at this point.
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Activity
Help
Changes of state
I4a
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W Use this sheet to help you record your results and draw conclusions.
p
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t
u
Presenting the results
100
TN TC
Considering the evidence
1 Did the temperature go down
90
Temperature in °C
Draw a sketch of the graph shown on
^ _ the computer (or your teacher may give
UG LP you a printout).
80
70
60
50
40
30
steadily all the time?
20
10
2 a
When did the temperature go
0
1
2
3
down fastest?
4
5 6 7 8
Time in minutes
9
10
b When did the temperature go down slowest?
3 Use the graph to work out the melting point of the stearic acid.
°C
4 Complete the sentences by choosing some of the words below.
temperature
join
solid
gas
liquid
cooling
melting
quickly
When the stearic acid cooled down it changed from
. While it changed, its
particles were moving more
boiling
slowly
to
stayed the same. The
and started to
together. The temperature that this happened at is called the
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point.
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Changes of state
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Activity
Extension
W As a liquid cools, its particles move more slowly and it turns
into a solid. You are going to look at the cooling curve for
?
stearic acid as it changes state.
u
^ _
UG LP
Equipment
●
●
TN TC
●
●
●
●
●
●
Bunsen burner
boiling tube of stearic acid
beaker of water
clamp stand
tripod and gauze
temperature probe
computer and interface
datalogging software
Wear eye
protection.
Take care with
hot water and
hot stearic acid.
Do not remove the
temperature probe from
solid stearic acid.
boiling tube
Wash your hands, stearic
acid can be harmful.
water
tripod
Bunsen burner
Planning and predicting
1 Predict what will happen to the temperature of the liquid at the
point that it solidifies.
2 Explain why you think this.
1 Plan an investigation to prove your prediction. Ask your teacher
to approve your plan.
Obtaining evidence
2 Carry out your investigation and display your results.
Considering the evidence
3 Describe the shape of your graph. Does this match your
prediction?
4 What was the temperature reading when it stopped falling?
5 Use the graph to work out the melting point of the stearic acid.
6 Explain in detail what is happening to the stearic acid particles at
this point.
Evaluating
7 a Describe how you could have carried out this investigation
using a thermometer instead of a datalogger.
b Which method is the most accurate? Explain why.
8 Describe how you could modify your investigation to prove that
melting and freezing occur at the same temperature. If you have
time, carry it out.
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How quickly does heat travel?
I5a
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TC
6
Teacher
activity notes
Type
Purpose
Differentiation
Practical
Demonstration to show pupils how heat energy is transferred along a metal bar by
conduction.
Core, Extension
Running the activity
This experiment can be done as a pupil experiment, but the result is a lot of very hot bars
around the laboratory. Pupils can take part in the demonstration by timing (and predicting the
time) when the drawing pins fall. Vaseline is preferable to candle wax for fixing the drawing
pins to the bar, as it melts more easily.
Expected outcomes
Core: Pupils see the vaseline melt and the pins drop. The pins nearest the flame fall first. The
particles in the bar pass the energy from one to the next.
Extension: In their predictions, pupils might expect that the times between each pin falling
would be equal. Pupils calculate the speed with which the heat was transferred to the first and
last pin and compare this with the graph to see if they match. From the graph they should see
that the time between each pin is not equal as the rate of heat flow will slow down further
along the bar, as the temperature gradient decreases.
Pitfalls
About five drawing pins is the maximum, or it takes forever for the last ones to fall. Pupils will
have difficulty recording minutes and part minutes – decide whether they should work in
minutes and seconds, or minutes and decimals, or change to measure time in seconds. This is
an extra complication if pupils are plotting a graph.
Safety notes
The bar gets very hot, stays hot for a long time, and doesn’t look hot.
ICT opportunities
It would be possible to set up a spreadsheet for the results and subsequent calculations of speed,
and to draw the line graph.
Answers
Core:
1 Pupils should predict that the heat will be transferred along the rod and cause the vaseline to
melt and the pins to fall. 2 Pupils should see that the time between each pin dropping gets
longer as you move away from the flame. 3 Pupils should describe that as the heat energy
reaches the particles they vibrate more and the energy is transferred from one particle to the
next by the vibrations.
Extension:
1 Pupils should predict that the heat will be transferred along the rod and cause the vaseline to
melt and the pins to fall. 2 In their predictions, pupils might expect that the times between
each pin falling would be equal. Some pupils may predict that the time between each pin is not
equal as the rate of heat flow will slow down further along the bar, as the temperature gradient
decreases. 3 The graph should have distance (in cm) on the horizontal axis, and time (in
minutes) on the vertical axis. It should be a line graph.
4 Pupils calculate speed = distance divided by time. If the energy travelled at a constant speed
then the graph would be a straight line, and the numbers equal. 5 The experiment can be
criticised as there is no measurement of how much vaseline is used. 6 Heat is lost to the
surroundings. Insulating the bar would prevent this (but is not practicable for this set up!). With
a very long bar eventually there would be no more heat flow along the bar, all would be lost to
the surroundings.
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How quickly does heat travel?
I5a
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UG LP
TN
Technician
activity notes
Type
Purpose
Differentiation
Practical
Demonstration to show pupils how heat energy is transferred along a metal bar by
conduction.
Core, Extension
Equipment
For each group/demonstration
● metal bar, e.g. vertical from retort stand
● retort stand, boss and clamp
● four drawing pins
● vaseline or candle wax
● Bunsen burner
● stopclocks for whole class
Unscrew the vertical from a retort stand and use
another retort stand, boss and clamp to hold it
horizontally. The clamp must be at one (the screw)
end of the bar, even if it does sag a little bit. You may
need to weigh down the retort stand base to keep it
stable.
clamp
stand
pins fixed
at regular
intervals
metal rod
Bunsen
burner
Fix five drawing pins to the lower edge of the bar
with vaseline. The first pin should be 3 or 4 cm from
the end of the bar, and the other three spaced at
equal 3 or 4 cm intervals.
For your information
Running the activity
This experiment can be done as a pupil experiment, but the result is a lot of very
hot bars around the laboratory. Pupils can take part in the demonstration by
timing (and predicting the time) when the drawing pins fall. Vaseline is preferable
to candle wax for fixing the drawing pins to the bar, as it melts more easily.
Expected outcomes
Core: Pupils see the vaseline melt and the pins drop. The pins nearest the flame fall
first. The particles in the bar pass the energy from one to the next.
Extension: In their predictions, pupils might expect that the times between each
pin falling would be equal. Pupils calculate the speed with which the heat was
transferred to the first and last pin and compare this with the graph to see if they
match. From the graph they should see that the time between each pin is not
equal as the rate of heat flow will slow down further along the bar, as the
temperature gradient decreases.
Pitfalls
About five drawing pins is the maximum, or it takes forever for the last ones to
fall. Pupils will have difficulty recording minutes and part minutes – decide
whether they should work in minutes and seconds, or minutes and decimals, or
change to measure time in seconds. This is an extra complication if pupils are
plotting a graph.
Safety notes
The bar gets very hot, stays hot for a long time, and doesn’t look hot.
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Print Lesson I7 Evaporation, radiation (18 pages)
I5a
M
How quickly does heat travel?
p
W Your teacher is going to demonstrate how heat is transferred
along a bar by conduction.
?
t
u
clamp
stand
^ _
Activity
Core
Be careful! The
metal bar gets
very hot and
takes a long time to cool
down. Don’t touch it!
metal rod
UG LP
TN TC
pins fixed
at regular
intervals
Bunsen
burner
Predicting
1 The drawing pins are held on with candle wax. What will happen
as one end of the rod is heated?
Obtaining evidence
1 Your teacher will heat one end of the bar. Copy and complete a
results table like this.
Distance of pin from flame in cm
Time to fall in minutes
Considering the evidence
2 Write a sentence to describe any pattern you can see from your
observations.
3 Explain how heat travelled along the bar. Use the word ‘particles’
in your answer.
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Print Lesson I7 Evaporation, radiation (18 pages)
I5a
M
p
t
How quickly does heat travel?
W Your teacher is going to demonstrate how heat is transferred
along a bar by conduction.
?
clamp
u
stand
metal rod
Activity
Extension
Be careful! The
metal bar gets
very hot and
takes a long time to cool
down. Don’t touch it!
^ _
UG LP
TN TC
TC
pins fixed
at regular
intervals
Bunsen
burner
Predicting
1 The drawing pins are held on with candle wax. What will happen
as one end of the rod is heated?
2 The drawing pins are equally spaced. Make a prediction about
whether the pins will fall at equal time intervals.
Obtaining evidence
1 Your teacher will heat one end of the bar. Draw up a results table
to record the distance of the pins from the flame, and the time
when they fall.
Considering the evidence
3 Draw a distance– time graph to show how long it took the heat
to transfer along the bar.
4 Calculate the speed that the heat energy travelled along the bar to:
a the first pin
b the last pin.
Are your two answers the same? Could you tell from your graph
whether they should be?
Evaluating
5 Was this experiment accurate? How could the experiment be
improved?
6 Was all the energy transferred along the bar? What do you think
would happen if you used a very long bar?
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Page 43
Print Lesson I7 Evaporation, radiation (18 pages)
House insulation
I5b
M
p
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t
u
^ _
UG LP
6
Teacher
activity notes
Type
Purpose
Differentiation
Paper
To reinforce understanding of thermal conductors and insulators; and to see some
practical applications of conduction and insulation.
Core (Extension)
Running the activity
Pupils answer the questions on the pupil sheet using their knowledge of
conduction and insulation, and applying it to some practical applications.
Answers
Core:
1 Particles in a gas like air are much further apart than those in a solid, so they do
not bump into each other as much, so it is more difficult for the particles to
pass on the energy.
2 Roof space/loft – stop heat being lost through roof to outside.
Cavity walls – stop heat being lost through walls to outside.
Windows – stop heat being lost through windows to outside.
Carpets – stop heat being lost through floors to ground.
3 Good conductors – oven shelves, hob rings, pans, casserole dishes, kettle
elements. Good insulators – oven and fridge doors, pan handles, oven gloves,
bodies of electric kettles.
Extension
4 Fur traps air, which is an insulator. On the inside it would trap the air more
efficiently.
5 a There are more layers of trapped air which insulate better.
b Fluffing up the duvet traps more air between the feathers/filling which
insulates better.
6 a 40 years.
b Sound insulation. Plastic frame requires less maintenance than wooden one.
Wooden frame may be rotten and need replacing anyway, so cost is
difference in prices, not total cost.
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Print Lesson I7 Evaporation, radiation (18 pages)
House insulation
I5b
M
W
p
?
t
u
^ _
UG LP
TN
Activity
Core
1 Explain why air is a better insulator than
solids like metal, brick and wood. (Hint:
Think of the way the particles are arranged
in solids and gases.)
2 Each of the inset pictures shows something
that traps air inside it. Make a list of the
four ways the house is insulated. For each
one, explain where it stops the heat in the
house being transferred to.
3 In the kitchen there are jobs for good
conductors and for good insulators. Make
a list of as many as you can think of.
glass
glass
air
double
glazing
fibreglass
insulation
foam brick
carpet
cavity walls
Extension
4 Explain why a fur-fabric coat might be warmer if you wear it
inside out.
5 a
Several layers of blankets are warmer than one thick blanket.
Explain why this should be.
b Explain why you should ‘fluff up’ a duvet to be warmer.
6 aa To have a window replaced by one that is double glazed costs
£200. The energy saved every year by just one window costs
£5. How many years would it take for the double glazing to
‘pay for itself’?
b What other reasons are there, besides heat insulation, for
fitting double glazing?
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Print Lesson I7 Evaporation, radiation (18 pages)
Convection in a liquid
I6a
M
p
?
t
u
^ _
UG LP
TC
6
Teacher
activity notes
Type
Purpose
Differentiation
Practical
Demonstration to show pupils convection currents in a liquid.
Core (Help)
Running the activity
Pupils should work in pairs. Placing the crystal at the bottom and to the side of
the water is fiddly. It would be worth demonstrating the technique to the pupils
and emphasising how difficult it is not to stir the water and spread the dye
throughout the liquid. Instructions are given on the activity sheet. Heating must
be gentle. It would be best if the teacher visited each group, to help them turn
down the gas and place the burner in the correct position. Pupils need to be
encouraged to record their observations while the convection current is being set
up.
Core: Pupils follow the instructions on the sheet and answer the questions.
Help: Pupils are given more guidance with the conclusion.
Expected outcomes
The water around the crystal becomes purple as the dye dissolves. The water on
the side of the beaker being heated expands, becomes less dense and rises, taking
the dye with it. The cooler, denser water away from the flame falls. As the
convection current is set up, the purple dye falls with the denser water that is
away from the flame.
Pitfalls
The crystals must be placed carefully. Heating must be gentle (turn the gas down).
Safety notes
Eye protection should be worn. Care should be taken not to touch hot apparatus.
The dye crystals – potassium manganate(VII) – should be handled with tweezers.
Care should be taken not to get dye on skin or clothes.
Answers
Core:
1 The purple dye dissolves in the water close to the crystal. The purple dye rises
on the side of the beaker that is heated. The purple dye falls on the side of the
beaker away from the flame.
2 Dissolving and convection.
3 The answers will reflect the understanding of the pupil. If the pupil has been
using the red book, their answer should refer to density, and possibly to
particles. If using the green book, their answer will be restricted to hotter liquid
rising and cooler liquid falling.
a The crystal is soluble and dissolves in the water.
b (Green book users) It is hotter and therefore rises. (Red book users) The
particles in the water vibrate more, and take up more space. This means the
liquid is less dense than the liquid around it, and rises.
c (Green book users) It is cooler and therefore sinks. (Red book users) The
particles in the water are vibrating less than the particles above the flame.
They therefore take up less space. This means the liquid is more dense than
the liquid around it, and falls.
Help:
4 Dissolves, rises, falls, convection, convection current.
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Print Lesson I7 Evaporation, radiation (18 pages)
Convection in a liquid
I6a
M
p
?
t
u
^ _
UG LP
TN
6
Technician
activity notes
Type
Purpose
Differentiation
Practical
Demonstration to show pupils convection currents in a liquid.
Core (Help)
Equipment
For each pair:
●
●
●
●
●
●
●
250 cm3 beaker
tripod
gauze
Bunsen burner
heatproof mat
wide plastic straw
tweezers
For the class:
●
four small labelled pots of potassium manganate(VII) crystals
For your information
Running the activity
Pupils should work in pairs. Placing the crystal at the bottom and to the side of
the water is fiddly. It would be worth demonstrating the technique to the pupils
and emphasising how difficult it is not to stir the water and spread the dye
throughout the liquid. Instructions are given on the activity sheet. Heating must
be gentle. It would be best if the teacher visited each group, to help them turn
down the gas and place the burner in the correct position. Pupils need to be
encouraged to record their observations while the convection current is being set
up.
Core: Pupils follow the instructions on the sheet and answer the questions.
Help: Pupils are given more guidance with the conclusion.
Expected outcomes
The water around the crystal becomes purple as the dye dissolves. The water on
the side of the beaker being heated expands, becomes less dense and rises, taking
the dye with it. The cooler, denser water away from the flame falls. As the
convection current is set up, the purple dye falls with the denser water that is
away from the flame.
Pitfalls
The crystals must be placed carefully. Heating must be gentle (turn the gas down).
Safety notes
Eye protection should be worn. Care should be taken not to touch hot apparatus.
The dye crystals – potassium manganate(VII) – should be handled with tweezers.
Care should be taken not to get dye on skin or clothes.
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Print Lesson I7 Evaporation, radiation (18 pages)
I6a
Convection in a liquid
p
W You are going to set up a convection current in a liquid, and
observe it using a purple dye.
?
t
u
Wear eye
protection.
Beware of
hot objects.
Obtaining evidence
^ _ 1 Fill a beaker with water. Place it on a tripod and gauze
as shown in the first diagram.
UG LP 2 Place a plastic drinking straw into the water so that the end is
just off the bottom of the beaker.
TN TC
3 Pick up a crystal of purple dye with tweezers. Drop the crystal
down the straw, so that it lands on the bottom of the beaker.
4 Remove the straw very slowly, so as not to disturb the crystal.
5 Gently heat the water under the crystal, as shown in the
second diagram. Use a blue flame with the gas turned down.
Do not touch the
purple dye.
plastic straw
water
crystal of
purple dye
x
x
x
x
x
x
x
x
x
x
x
M
Activity
Core
1 Describe carefully what you see happening in the beaker.
Draw diagrams if this helps.
water
crystal of
purple dye
x
x
x
x
x
x
x
x
x
x
x
Considering the evidence
2 Name two processes happening in the beaker.
3 Explain the following:
Bunsen
burner
a why the water around the crystal becomes purple
b why the purple dye rises above the flame
c why the purple dye falls on the side away from the flame.
Help
Considering the evidence
4 Complete the sentences to describe what is happening inside the
beaker by choosing some of the words below.
melts
convection
conduction
convection cu
rrent
rises
insulator
falls
conductor
dissolves
The purple dye
in the water close to the crystal.
The purple dye
on the side of the beaker that is heated.
The purple dye
on the side of the beaker away from the flame.
This is one example of
.
The movement of water is called a
© Harcourt Education Ltd 2004 Catalyst 2
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.
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Print Lesson I7 Evaporation, radiation (18 pages)
Convection currents around us
I6b
M
p
?
t
u
^ _
Teacher
activity notes
Type
Purpose
Differentiation
Paper
To improve pupils’ understanding by explaining phenomena.
Core, Help, Extension
Running the activity
The activity is available at three levels but the contexts (sea breezes and hot water tanks) are common to
all. Pupils should work alone or in pairs.
UG LP Core: This version is structured to tease out the explanation.
Help: This requires almost no writing.
Extension: This version gives little or no guidance.
Expected outcomes
Pupils can explain sea breezes in terms of a convection current, and why putting the heating element at
the top of a hot water tank is ill-advised.
Answers
Core:
1 Rise. The air above the land is hotter than the surrounding air, because the land has heated it.
2 Once the heated air above the land has risen, cool air from over the sea will move in to take its place.
3
4 A
The sea is cooler than the
land. The air above the sea
is heated less than the
air above the land.
B
The land is hotter than
the sea. The air above
the land is hotter than
the air above the sea.
5 rise 6 The heated water is already at the top of the tank, so it stays at the top, unable to rise further.
The water will continue to be heated, but the water in the tank will not mix. 7 The heated water rises
and cold water moves down to take its place. This cold water is then heated. The resulting convection
current ensures that all the water in the tank is heated evenly.
Help:
1 Rise – see diagram above (arrow above land). 2 Sink – see diagram above (arrow above sea). 3 See
diagram above (circling arrows). 4 Away from the sea. 5 The water around the heaters – see shaded
area on tank diagrams above. 6 Rise – see diagrams above. 7 B 8 A
Extension:
1 See diagram above. The air above the land is heated more than the air above the sea. This is because
the land is hotter than the sea. The air over the land expands more than the air above the sea. This means
that the air above the land is less dense than the air around it and rises, and the cooler, denser air from
above the sea moves in to take its place. This means that there is movement of air from the sea to the land,
and the air from the sea will be cooler than the air above the land, so will be felt as a cooling breeze.
2 See tank diagrams above. Placing the heater at the top of the tank only heats the water at the top of the
tank. The hot water is less dense than the cold water, so the hotter water rises and the colder water sinks.
This means that the cold water at the bottom will never come in contact with the heater. If the heater is
placed at the bottom of the tank the heated water will rise and unheated water will fall to take its place.
In this way all the water in the tank will be heated.
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Print Lesson I7 Evaporation, radiation (18 pages)
I6b
M
Activity
Core
Convection currents around us
p
W You are going to use your knowledge and understanding of
convection to explain some observations.
?
t
u
^ _
UG LP
TN
The sea is cooler than the
land. The air above the sea
is heated less than the
air above the land.
The land is hotter than
the sea. The air above
the land is hotter than
the air above the sea.
1 Look at the diagram. It shows the air, the sea and the land on a
hot day in summer.
1 Will the air above the land rise or sink? Give a reason for your
answer.
2 Explain why people on the land would feel a cooling breeze.
3 Draw your own version of the diagram. Add arrows to show how
the air moves.
2 Hot water tanks contain a heater that heats
the water. The heater is a coil of metal that is
heated using electricity.
A
heater at
top of tank
When the heater is put at the top of the tank,
as in tank A, only the water at the top of the
tank is heated.
When the heater is put at the bottom of the
tank, as in tank B, all the water in the tank is
heated.
cold
water in
B
4 Copy the diagrams of the hot water tanks.
Think about what part of the water will heat
first in each tank. Shade that water lightly in
red.
5 Does hot water rise or fall?
6 Explain why only the water at the top heats
up in tank A.
7 Explain how all the water in tank B heats up.
© Harcourt Education Ltd 2004 Catalyst 2
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heater at
bottom of tank
cold
water in
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Print Lesson I7 Evaporation, radiation (18 pages)
I6b
M
Activity
Help
Convection currents around us
p
W You are going to use your knowledge and understanding of
convection to explain some observations.
?
t
u
^ _
UG LP
TN
The sea is cooler than the
land. The air above the sea
is heated less than the
air above the land.
The land is hotter than
the sea. The air above
the land is hotter than
the air above the sea.
1 Look at the diagram. It shows the air, the sea and the land on a
hot day in summer.
1 Will the air above the land rise or sink? Draw an arrow above the
land to show the movement of the air.
2 Will the air above the sea rise or sink? Draw an arrow above the
sea to show the movement of the air.
3 Add two more arrows to complete the convection current.
4 Draw a person flying a kite on the land. Which
A
way would the kite fly?
2 Hot water tanks contain a heater that heats
the water.
heater at
top of tank
5 Think about what part of the water will heat
first in each tank. Shade that water lightly in
red.
6 Does hot water rise or fall? Add red arrows in
each tank to show the heated water moving.
cold
water in
B
7 In which tank will the hot water mix with the
cold water?
8 In which tank will the hot water stay at the
top and the cold water at the bottom?
© Harcourt Education Ltd 2004 Catalyst 2
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heater at
bottom of tank
cold
water in
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Print Lesson I7 Evaporation, radiation (18 pages)
I6b
M
Activity
Extension
Convection currents around us
p
W You are going to use your knowledge and understanding of
convection to explain some observations.
?
t
u
^ _
UG LP
TN
The sea is cooler than the
land. The air above the sea
is heated less than the
air above the land.
The land is hotter than
the sea. The air above
the land is hotter than
the air above the sea.
1 Look at the diagram. It shows the air, the sea and the land on a
hot day in summer.
1 Make a copy of the diagram. Add arrows to show the movement
of the air. Explain in as much detail as you can why a cooling sea
breeze blows on a hot summer’s day.
2 Hot water tanks contain a heater that heats the
water. The heater is a coil of metal that is
heated using electricity.
A
heater at
top of tank
When the heater is put at the top of the tank,
as in tank A, only the water at the top of the
tank is heated.
When the heater is put at the bottom of the
tank, as in tank B, all the water in the tank is
heated.
cold
water in
B
2 Copy diagrams A and B and label them to
explain why the heater should be placed at the
bottom of the tank.
heater at
bottom of tank
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cold
water in
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Print Lesson I7 Evaporation, radiation (18 pages)
Cooling by evaporation
I7a
M
p
?
t
u
^ _
UG LP
TC
6
Teacher
activity notes
Type
Purpose
Differentiation
Practical
Demonstration to show that evaporation causes cooling.
Core (Extension)
Running the activity
The set-up will depend on the equipment available. If equipment is limited, you
may choose to demonstrate the activity. The temperature of the three pieces of
cotton wool should be measured for 10 minutes, with the outputs from all three
probes being displayed in graphical form on the screen. Pupils then use the
activity sheet to guide them through writing an explanation of cooling by
evaporation.
Core: Pupils write their own explanation using words given.
Extension: Pupils are asked to speculate on the difference between water and
ethanol.
Expected outcomes
The dry cotton wool should maintain a steady temperature. Both the water-soaked
and the ethanol-soaked cotton wool should cool, with the ethanol-soaked cotton
wool cooling more rapidly.
Pitfalls
The measurements should be taken as soon as the ethanol and water are added to
the cotton wool. Delay may mean that all the ethanol evaporates before any
measurements are taken.
Safety notes
Ethanol is highly flammable; there should be no naked flames in the vicinity.
Answers
Core:
1 B
2 C
3 The liquid evaporates, turning into a gas. When this happens the particles with
more energy leave the liquid. This means that the particles in the liquid have less
energy (on average), so the temperature of the liquid decreases.
4 Temperature probes A and B would return to room temperature.
Extension:
5 (Most pupils) The ethanol must have evaporated more quickly than the water.
(Exceptional pupils) The forces of attraction between the ethanol particles must
be weaker than those between the water particles, because more particles in the
ethanol had enough energy to leave the liquid.
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Print Lesson I7 Evaporation, radiation (18 pages)
Cooling by evaporation
I7a
M
p
?
t
u
^ _
UG LP
TN
6
Technician
activity notes
Type
Purpose
Differentiation
Practical
Demonstration to show that evaporation causes cooling.
Core (Extension)
Equipment
For each group / teacher demonstration:
● three temperature probes
● three clamp stands, bosses and clamps
● cotton wool to wrap around temperature probes
● three elastic bands to secure cotton wool
● interface
● computer
● software so that data from temperature probes can be displayed
For the class:
water in labelled wash bottle
● ethanol in labelled wash bottle
●
For your information
Running the activity
The set-up will depend on the equipment available. If equipment is limited, the
teacher may choose to demonstrate the activity. The temperature of the three
pieces of cotton wool should be measured for 10 minutes, with the outputs from
all three probes being displayed in graphical form on the screen. Pupils then use
the activity sheet to guide them through writing an explanation of cooling by
evaporation.
Core: Pupils write their own explanation using words given.
Extension: Pupils are asked to speculate on the difference between water and
ethanol.
Expected outcomes
The dry cotton wool should maintain a steady temperature. Both the water-soaked
and the ethanol-soaked cotton wool should cool, with the ethanol-soaked cotton
wool cooling more rapidly.
Pitfalls
The measurements should be taken as soon as the ethanol and water are added to
the cotton wool. Delay may mean that all the ethanol evaporates before any
measurements are taken.
Safety notes
Ethanol is highly flammable; there should be no naked flames in the vicinity.
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
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Print Lesson I7 Evaporation, radiation (18 pages)
Cooling by evaporation
I7a
M
Activity
Core
p
W You are going to use temperature probes to monitor cooling by
evaporation.
?
t
u
temperature
^ _ probe A
temperature
UG LP probe B
TN TC temperature
probe C
A BC
interface
cotton wool
1
2
3
4
Soak the cotton wool around temperature probe A with water.
Soak the cotton wool around temperature probe B with ethanol.
Leave the cotton wool around temperature probe C dry.
Monitor for 10 minutes, displaying the output from all three
temperature probes.
1 Which temperature probe was cooled the most?
2 Which temperature probe was cooled the least?
3 Explain why the temperature of the liquids around temperature
probes A and B decreased. Use these words in your explanation:
particles
temperature
energy
evaporates
liquid
gas
less
more
4 Predict what would happen when all the liquid had evaporated
from the cotton wool around temperature probes A and B.
Extension
5 Suggest why the temperature of probe B fell more quickly than
the temperature of probe A.
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Print Lesson I7 Evaporation, radiation (18 pages)
Radiation
I7b
M
p
?
t
u
^ _
UG LP
TC
6
Teacher
activity notes
Type
Purpose
Differentiation
Practical
Demonstration to show that shiny silver surfaces reflect more infrared radiation than
matt black surfaces.
No pupil sheets
Running the activity
This is a quick but effective teacher demonstration. One of two aluminium foil pie
dishes is painted matt black on one surface. A coin is stuck to the other surface
using wax. A coin is also stuck with wax to the same surface of the unpainted pie
dish. A Bunsen burner is lit and the teacher holds the pie dishes equidistant from
the flame (about 15 cm) using retort stands and clamps, with the coins away from
the flame. During the demonstration the teacher should remind the pupils that
infrared radiation is like light, and that light is absorbed by black surfaces but
reflected by silver surfaces.
Expected outcomes
The wax holding the coin in the painted pie dish melts first and the coin drops
off. After a delay, the other coin drops off. Pupils should understand that the shiny
pie dish reflects infrared heat back and so doesn’t heat up as much as the matt
black pie dish which absorbs heat.
Safety notes
Warn pupils not to touch the hot aluminium pie dishes.
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
Sheet 1 of 1
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Radiation
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Technician
activity notes
Type
Purpose
Differentiation
Practical
Demonstration to show that shiny silver surfaces reflect more infrared radiation than
matt black surfaces.
No pupil sheets
Equipment
For the teacher demonstration:
UG LP
●
TN
●
●
●
●
●
one aluminium pie dish
one aluminium pie dish painted matt black on underside
two coins (e.g. 1p)
candle so that coins can be fixed to dishes
Bunsen burner
two retort stands and clamps
For your information
Running the activity
This is a quick but effective teacher demonstration. One of two aluminium foil pie
dishes is painted matt black on one surface. A coin is stuck to the other surface
using wax. A coin is also stuck with wax to the same surface of the unpainted pie
dish. A Bunsen burner is lit and the teacher holds the pie dishes equidistant from
the flame (about 15 cm) using retort stands and clamps, with the coins away from
the flame. During the demonstration the teacher should remind the pupils that
infrared radiation is like light, and that light is absorbed by black surfaces but
reflected by silver surfaces.
Expected outcomes
The wax holding the coin in the painted pie dish melts first and the coin drops
off. After a delay, the other coin drops off. Pupils should understand that the shiny
pie dish reflects infrared heat back and so doesn’t heat up as much as the matt
black pie dish which absorbs heat.
Safety notes
Warn pupils not to touch the hot aluminium pie dishes.
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I-Teachers.qxd
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Print Lesson I7 Evaporation, radiation (18 pages)
The vacuum flask
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UG LP
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Teacher
activity notes
Type
Purpose
Differentiation
Paper
Pupils apply the ideas studied in the last three lessons to explain how a vacuum flask
works.
Core
Running the activity
If there is a vacuum flask available, especially one that can be taken apart, set the
scene by showing it to pupils. An old, broken one can be used to demonstrate the
double skin, but be careful with sharp broken glass.
ICT opportunities
Pupils could search the Internet for further information about James Dewar and
the vacuum flask.
Answers
1 To reduce radiation by reflecting heat.
2 Conduction and convection.
3 The top should be insulating.
4 evaporation
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I-Activities.qxd
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Print Lesson I7 Evaporation, radiation (18 pages)
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TN
Activity
Core
The vacuum flask
W You are going to learn about Sir James Dewar, a Scottish scientist
who lived over a hundred years ago. He invented a container to
?
keep very cold liquids cold that is very useful today.
u
James Dewar (1842– 1923) was interested in what happened at very
_ low temperatures. He worked on liquefying the gases in air
LP (changing them from gases to liquids). By 1885 he could produce
large quantities of liquid oxygen. By 1898, he was the first scientist
to cool hydrogen gas to its boiling point of −252°C. In 1899, he was
able to solidify it at −259°C.
Dewar needed a way to keep these liquids very cold, and in 1892 he
invented the first vacuum flask (sometimes called a thermos flask,
after the first commercial version, made in 1904).
A vacuum flask can keep hot things hot, and cold things cold!
stopper
vacuum
glass
silvered
surfaces
hot liquid
v
a
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liquid
glass
1 The double skin of the flask is made of glass, which is a poor
conductor. It is coated with a shiny silver coating on both inside
surfaces. What is the function of the coating?
2 Between the two layers making the double skin there is a
vacuum, which stops heat being transferred in two different
ways. What are these two ways?
3 The top of the flask in Dewar’s day had a cork stopper. Nowadays
it is usually hollow plastic. Why doesn’t the flask have a metal
top?
4 What kind of heat transfer does the top of the flask prevent when
it is put on the flask?
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Print Lesson I7 Evaporation, radiation (18 pages)
What affects how tea cools?
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Teacher
activity notes
Type
Purpose
Differentiation
Paper
Pupils analyse two cooling curves, and identify the variables in the experiment.
Core (Extension)
Running the activity
Pupils answer the questions on the pupil sheet to analyse the graph.
UG LP Answers
Core:
1 Beaker A.
2 There is more surface area, so more convection currents in the air above, and
more evaporation. In terms of particles, there are more air particles in contact
with the hot water to carry heat energy away in convection currents. There is
more chance for liquid particles to escape from the container with the larger
surface area by evaporation because it takes energy to break the bonds between
the liquid particles.
3 How much water, start temperature, room temperature, surface area (or size of
beaker), material of beaker, lid or not, insulation round beaker. N.B. Because
question says ‘how quickly’, time is not a variable as we are looking at rate.
4 They changed surface area (size of beaker); they controlled the rest.
5 Temperature or rate of cooling.
Extension:
6 Rate = (80 − 59)/10 = 2.1 °C/minute.
7 Curve A is steepest at the start, showing that the liquid cools fastest when it is
hottest, i.e. when the temperature difference between it and the surroundings is
biggest. The bigger the temperature difference, the more convection currents as
the greater the density difference between air in contact with the hot liquid,
and surrounding air; also the greater the rate of conduction through the beaker
sides. In addition evaporation is faster at higher temperatures.
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Print Lesson I7 Evaporation, radiation (18 pages)
What affects how tea cools?
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TN
W You are going to look at the cooling curves from two
different cups of tea and analyse them.
?
Sam and Alex had two mugs, one was 10cm across the
u
top, the other was only 5cm across. Both mugs were
_ made of plastic. They poured exactly 200cm3 of hot
LP water into each one, and put a temperature probe into
the water. When the temperature cooled to 80°C they
started recording, and recorded the temperature for 10minutes.
Here is the graph of their results.
100
1 Which beaker cooled down
2
3
4
5
Temperature in °C
M
Activity
Core
A
B
Cooling curves
80
fastest?
60
Suggest why this happened.
40
Use the words ‘energy’ and
20
‘particles’ in your answer.
0
0
2
4
6
8
Make a list of all the things
Time in minutes
that could affect how quickly
the water cooled down. These are
the independent variables.
Which of the independent variables did Sam and Alex change?
Which did they control?
What was the dependent variable in the experiment?
B
A
10
12
Extension
6 The temperature after 10 minutes in curve B is 59°C. Calculate
the cooling rate of the water, in °C per minute.
7 Look at curve A. Is it steepest at the start or at the end? What
does this show? Why do you think it happens?
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I-Plenaries.qxd
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Print Lesson I7 Evaporation, radiation (18 pages)
What temperature?
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Plenaries
Suggested alternative plenary activities (5–10 minutes)
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Review learning
Sharing responses
Group feedback
Pupils discuss why we need
thermometers.
Teacher-led discussion of
outcomes from Activity I1a.
In groups, pupils list different Pupils play hangman
kinds of thermometers, and
with the names of
say where each would be used. different types of
thermometer.
^ _
UG LP
Word game
Looking ahead
Remind pupils of the
particle model by arranging
groups of pupils to model a
solid and then a solid given
more energy to vibrate.
Review learning
●
Set the questions for individuals to consider and suggest
answers to. Then ask them to share their responses with
other pupils.
●
Pupils can summarise the suggestions and record them in
their books, to reconsider after further lessons.
●
Hold up each example thermometer in turn, and ask a
volunteer to describe how and where to use it.
Questions
Why do we need thermometers?
Why isn’t just feeling it good enough?
Sharing responses
●
Teacher-led discussion of the outcomes from Activity I1a.
●
Discuss and evaluate the accuracy of the water
thermometers made by gathering class results for the
temperatures measured.
Group feedback
●
Pupils work in groups to complete answers to the questions
on the pupil sheet.
●
Take suggestions from the groups and sum up on the
board.
Word game
●
Play a game of hangman with the whole class to reinforce
vocabulary and spelling.
●
Teacher puts up hangman dashes for each name of
thermometer, pupils guess letters until they guess the word.
➔ Pupil sheet
Answers
1 mercury: glass would crack,
temperature too high for scale,
mercury might boil/scale does not go
high enough
2 clinical: scale does not go low
enough
3 laboratory: not sensitive enough
Looking ahead
●
Ask a group of 12 to 16 pupils to model being a solid, with
each pupil having left hand on shoulder of pupil in front,
and right hand on shoulder of pupil at side. Say they are
given a small amount of energy to allow them to move and
vibrate more without breaking bonds. This may be best
done in a corridor or playground if the classroom is
crowded.
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What temperature?
Plenaries
Group feedback
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TN
6
1 Why would a mercury thermometer be
no good as an oven thermometer for
baking a cake at 200 °C?
2 Why would a clinical thermometer be
no good for measuring the
temperature outdoors throughout the
year?
3 Why would a laboratory alcohol
thermometer be no good for
measuring the temperature of a person
with a fever?
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Temperature and energy
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Suggested alternative plenary activities (5–10 minutes)
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Review learning
Sharing responses
Group feedback
Word game
Looking ahead
Show the pupils the learning
objectives again. Ask volunteers to
explain how the lesson has helped
them to achieve the objectives.
Pupils answer questions
about Activity I2a.
In groups, pupils complete
the sentences about the
difference between heat
and temperature.
Play the Taboo game.
A small group of pupils
model a solid as heat
energy causes increased
vibration and expansion.
UG LP Review learning
●
●
●
Pupils volunteer to explain how the lesson helped them achieve each objective.
Objective 1: The difference between energy and temperature is modelled in the
textbook as the total thermal energy of all the particles in the system; while the
temperature is the average kinetic energy per particle.
Objective 2: The two independent variables in the activity are quantity of water
and temperature rise, while the dependent variable is the quantity of energy
used. Pupils must appreciate that when there are two independent variables, one
must be controlled (they all used the same temperature rise).
Sharing responses
●
Pupils can use individual whiteboards (or ice cream tub lids) with whiteboard
pens to answer the questions read out from the teacher sheet so you can check
that all respond, and judge whether the lesson objectives have been learned. If
individual whiteboards are not available then pupils can volunteer to answer.
➔ Teacher sheet
Group feedback
●
●
●
Pupils work in pairs and then in fours to complete the sentences below. Ask a
volunteer for each group to read out an answer.
Questions
1 We explain the difference between heat and temperature by saying …
2 A large jug of hot water has more energy than a mug of hot water because …
3 A large mug of coffee cools down more slowly than a small cup because …
Answers
1 … heat is a kind of energy – the total energy that all the particles possess. It is
measured in joules with a joulemeter. Temperature is hotness, it depends on the
average kinetic energy of the particles. It is measured in degrees Celsius with a
thermometer or temperature probe. 2 … the large jug contains more water
particles, all with kinetic energy. 3 … the large mug has more particles,
and all the particles must lose some energy for the drink to cool down.
Word game
●
●
●
Pupils play Taboo using cards cut out from the pupil sheet.
Give one pupil a card with a mystery word on it. The pupil offers clues to the
class to allow them to identify the mystery word, but is not allowed to use the
given ‘taboo’ words in their clues.
You can adjust the level of challenge by banning the use of just the first, or first
and second words in the taboo list, and then increase the number later.
➔ Pupil sheet
Looking ahead
●
●
Ask 12 to 16 pupils to stand in a grid arrangement, modelling a solid with the
left hand on shoulder of pupil in front, right hand on shoulder of pupil at side.
Both arms should be kept bent at the elbow as much as possible. Initially they are
‘very cold’ – can’t move at all.
Say they are now supplied with energy and can move – but must keep both hands
touching neighbours’ shoulders but can now straighten arms. The group can be
seen to take up more space, modelling thermal expansion. The ‘particles’ get
further apart – they (the pupils) do not themselves expand.
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Temperature and energy
Plenaries
Sharing responses
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Teacher sheet
Read out the questions below to the class.
1 What do particles gain when they get hotter?
[energy]
^ _
2 What are the units of energy?
[Joules]
UG LP
3 What are the units of temperature?
TN
4 What independent variable did we change in the heating
experiment?
5 Which independent variable did we control in the heating
experiment?
6 What was the dependent variable in the heating experiment?
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
[°C]
[water volume]
[temperature rise]
[energy used]
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Word game
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TN
Temperature and energy
6
Temperature
Taboo
●
●
●
●
hotness
degrees
Celsius
thermometer
Joules
Taboo
●
●
●
●
heat
joulemeter
energy
unit
Energy
Taboo
●
●
●
heat
joules
joulemeter
Variable
Taboo
●
●
●
●
experiment
change
energy
values
Thermometer
●
Taboo
●
●
●
●
temperature
degrees
Celsius
hot
cold
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Bigger and smaller
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Plenaries
Suggested alternative plenary activities (5–10 minutes)
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Review learning
Sharing responses
Group feedback
Word game
Looking ahead
Pupils answer questions
with one (or two) word
answers with white boards,
or volunteer answers.
Whole-class feedback on
Activity I3a or Activity I3b.
Pupils produce a poster to
explain why a thermometer
works.
Pupils pair observations
with explanations correctly.
A small group of pupils
model a solid turning to
liquid and turning to gas.
UG LP Review learning
●
Pupils either answer on white boards (or lids of ice cream
tubs) so that a whole-class response can be quickly
gathered, or select volunteers to answer.
➔ Teacher sheet
Sharing responses
●
Sum up after the activity by asking volunteers to describe
first what they observed and then other volunteers to
explain the observations.
Group feedback
●
Pupils produce posters to explain how a thermometer
works (you need to specify a liquid in glass thermometer,
rather than a temperature probe, etc.), using expansion/
contraction ideas and including a diagram of particles.
●
The posters can be displayed for discussion now, or to
discuss as the starter for the next lesson.
Word game
●
Pupils work in pairs to match the observation with the
correct explanation.
●
Check the correct answers at the end. (This sheet could
be used as a starter for the next lesson.)
➔ Pupil sheet
Looking ahead
●
Ask 12 to 16 pupils to form a regular array, modelling a
solid with left hand on shoulder of person in front, right
hand on neighbour’s shoulder.
●
Tell pupils then to ‘melt’ and move so that they are
always touching at least one person, but keep swapping
partners (say every 3 seconds).
●
Then tell pupils to form a gas by walking freely in
straight lines, only changing direction when they collide
with a wall or each other.
●
With some classes you can extend this into a game by
calling ‘melt’, ‘boil’, ‘freeze’ ‘condense’, etc.
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Bigger and smaller
Plenaries
Review learning
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Teacher sheet
Read out the questions below to the class.
1 What is the word that means ‘getting bigger’?
[expansion]
^ _
2 What is the word that means ‘to do with heat’?
[thermal]
UG LP
3 Name something that bends when it is heated.
[bimetallic strip]
TN
4 Name something that uses thermal expansion of liquids.
5 Somewhere where a bimetallic strip is useful.
[thermostat]
6 Why couldn’t we use a rule to measure the expansion of
a metal rod?
7 Out of solids, liquids and gases which expands most?
8 Do particles get bigger when they get hotter?
9 What actually expands when something
is heated?
[thermometer]
[too small]
[gases]
[no]
[the space between the particles]
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Bigger and smaller
Plenaries
Word game
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Match the correct explanation to the observations:
^ _
Observation
Explanation
UG LP
Telephone wires always sag
between poles, they are
never stretched.
The tyre expanded when it
was hot, so it slipped round
the wheel easily, and then
when it cooled it held onto
the wheel tightly.
A gas-filled thermometer is
more sensitive than a liquidfilled one
The metal lid expands more
than the glass jar.
In the olden days the metal
‘tyres’ for cartwheels were
heated before being fitted
on the wheel.
If they were tight to begin
with, and the weather got
colder, they would snap as
they got shorter.
Putting a screw-topped jar
in hot water makes it easier
to open.
In flight, friction with the air
makes the plane heat up
and expand.
Furniture often creaks at
night.
Gases expand more than
liquids for the same
temperature rise.
Concorde is shorter before it
takes off than when it is
flying.
The furniture expands
during a hot day, and then
shrinks back during a cooler
night.
TN
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All change
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Plenaries
Suggested alternative plenary activities (5–10 minutes)
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Review learning
Sharing responses
Group feedback
Pupils write definitions for
Whole-class discussion of
In groups, pupils annotate
words relating to changes of the outcome of Activity I4a. the graph and explain to
state.
each other why the
temperature stays the same.
Problem solving
Looking ahead
Ask pupils why a steam
burn can be much more
serious than one from
boiling water.
A small group of pupils line
up as particles in a solid
and link arms, the end one
is heated and vibrates,
vibrations are passed along
to model conduction.
UG LP
Review learning
●
●
●
From the jumbled up words on the pupil sheet, pupils
decode the words relating to changes of state.
Then ask pupils to write a definition for each word –
more than one sentence is possible for each.
Take feedback from pupils. Summarise on the board.
Identify the importance of using scientific vocabulary.
➔ Pupil sheet
Answers
melting – solid to a liquid
boiling – liquid to a gas
condensation – gas to a liquid
freezing – liquid to a solid
Sharing responses
●
Whole-class discussion of the outcome of Activity I4a.
This should include the shape of the graph, how to read
the melting point off the graph and an explanation of
what is happening in terms of the particle model.
Group feedback
●
In groups, pupils look at the temperature–time graph on
the pupil sheet, which represents heating ice from –10 °C
to 120 °C. They discuss what is happening in each
section, and explain the shape of the graph.
➔ Pupil sheet
Problem solving
●
●
Set up a kettle with a temperature probe clamped in the
water (not touching the element) and connected to a
datalogger displaying a temperature graph.
When the kettle boils, point out the steam and ask for
suggestions as to why a burn from the steam would be
more serious than one from the boiling water. If the
explanation from pupils is not forthcoming, explain the
reason and check understanding.
Equipment
kettle (if it has automatic cut-off you may
have to hold the switch when it boils),
temperature probe and datalogger, retort
stand and clamp.
Safety: steam burns – be careful, especially
when holding in the cut-out switch.
Looking ahead
●
●
Ask 12 to 16 pupils to model heat conduction in a (nonmetallic) solid. They line up with linked arms in a line.
Tell them you have given heat energy to the end pupil,
who begins to jump around (still linked). This movement
is passed to the next in line, and so on.
Explain that this is a particle model of one way in which
heat energy can travel through a solid, and that next
lesson the class will see this in action.
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All change
Plenaries
Review learning
?
Rearrange the letters to form words, then write a dictionary
u definition of each word.
^ _
UG LP
TN
1 glmntie
3 nnntsdcaeioo
2 iiobgln
4 efigenrz
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
I4
All change
Sheet 1 of 1
Plenaries
Review learning
Rearrange the letters to form words, then write a dictionary
definition of each word.
1 glmntie
3 nnntsdcaeioo
2 iiobgln
4 efigenrz
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All change
Plenaries
Group feedback
Graph to show temperature as ice is
heated until it melts and then boils.
?
120
^ _ Label sections with the words ‘melting’
100
UG LP
and ‘boiling’.
Write a sentence to explain why some
parts of the graph are flat. Use the word
‘particles’ in your explanation.
TN
80
60
40
20
0
5
– 20
10
15
20
I4
Plenaries
Group feedback
Graph to show temperature as ice is
heated until it melts and then boils.
Label the graph with the words ‘solid’,
‘liquid’ and ‘gas’.
Write a sentence to explain why some
parts of the graph are flat. Use the word
‘particles’ in your explanation.
30
Sheet 1 of 1
All change
Label sections with the words ‘melting’
and ‘boiling’.
25
Time in minutes
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
120
100
Temperature in °C
t
Temperature in °C
Label the graph with the words ‘solid’,
u ‘liquid’ and ‘gas’.
80
60
40
20
0
5
– 20
© Harcourt Education Ltd 2004 Catalyst 2
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10
15
20
25
30
Time in minutes
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Conduction
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Plenaries
Suggested alternative plenary activities (5–10 minutes)
p
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Review learning
Sharing responses
Group feedback
Word game
Looking ahead
t
u
Play ‘Give me three’ with
examples of conductors and
insulators.
In pairs, pupils complete
sentences and compare
their answers with another
group to summarise what
they learnt from Activity
I5a.
In groups, pupils discuss
the answers to Activity I5b.
Word search with conductor,
insulator, then different
examples; after finding
words pupils put them into
two groups.
Demo a spiral above small
Bunsen flame, and ask
pupils to suggest why this
happens.
^ _
UG LP
Review learning
●
Ask pupils to give three examples for each category
opposite. Pupils can either answer on individual white
boards, or volunteers can suggest answers.
Sharing responses
●
Pupils work in pairs to complete the sentences opposite.
Then compare their answers with another pair.
Categories
places where you need a good heat
conductor/places where you need a good
heat insulator/places where trapped air
acts as an insulator
Sentences
the experiment with the long bar and the
drawing pins showed us that
/we know that some things are better
conductors than others because
/insulation is used all round a house, for
example
Group feedback
●
In groups, pupils compare their answers to Activity I5b
and especially see how long a list of examples they can
come up with for question 3.
Word game
●
Ask pupils to complete the wordsearch on the pupil
sheet.
●
Ring the words on a copy of the pupil sheet and show it
as an OHT for them to check their answers. Use the
words on it to introduce the lesson.
➔ Pupil sheet
Looking ahead
●
Demonstrate a suspended paper spiral rotating above a
small Bunsen flame, or a Christmas decoration where
convection currents from candle flames cause movement.
●
Explain that next lesson they will find out how this
works.
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Conduction
I5
M
p
t
Plenaries
Word game
?
All these words are connected with conduction. See how many of
u them you can find in the wordsearch.
^ _ Then divide them into two groups: one of good conductors and one
UG LP
TN
of bad conductors.
conductor
solder
insulator
metal
handle
welding rod
glove
oven shelf
anorak
air
o
d
e
t
c
a
r
z
a
n
v
u
r
t
o
r
e
g
z
a
e
x
h
a
n
d
l
e
y
n
n
s
o
l
d
e
r
w
v
o
s
i
n
s
u
l
a
t
o
r
h
q
e
r
c
s
t
i
u
a
e
p
o
v
t
n
m
l
r
k
l
d
e
f
o
g
h
i
j
k
f
c
b
a
r
l
a
t
e
m
w
e
l
d
i
n
g
r
o
d
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Convection
I6
M
6
Plenaries
Suggested alternative plenary activities (5–10 minutes)
p
?
Review learning
t
u
Play ‘Give me three’ and ask Whole-class discussion of
for differences between
Activity I6a.
conduction and convection.
Sharing responses
^ _
Group feedback
Word game
Looking ahead
In groups, pupils use the
experiments they have seen
to describe what a
convection current is, and
why it happens.
Create a ‘poem’ based on
the word convection.
Wipe a little surgical
spirit/ethanol/water on
pupils’ skin, or wet one
hand and direct a cold fan
at both hands and observe
the temperature difference.
UG LP
Review learning
●
Ask pupils to give three differences between conduction
and convection.
Answers
Conduction is best in solids; convection is
only in liquids and gases; heat can travel
in any direction by conduction; heat can
only travel upwards by convection; in
conduction only the energy travels; in
convection the material does too.
Sharing responses
●
Ask volunteers to describe what they observed in Activity
I6a. Then ask for other volunteers to explain why this
happened.
Answers
Lower ability: particles rise and transfer
energy until temperature is the same in all
of the liquid.
Higher ability: relate to thermal expansion
in liquids and lower density causing liquid
to rise until temperature is the same in all
of the liquid.
Group feedback
●
In groups, pupils discuss how they would use the
experiments they have seen to describe what a
convection current is, and explain why it happens.
●
Collect responses from groups and summarise on the
board.
Word game
●
Pupils create a ‘poem’ by writing the word CONVECTION
down the page, and writing sentences about the key ideas
in the lesson going across.
●
Show them the example for CONDUCTION from the
teacher sheet to inspire them.
➔ Teacher sheet
Looking ahead
●
Wipe a little surgical spirit/ethanol/water on pupils’ skin,
or wet one of a pupil’s hands and direct a cold fan at
both hands. Ask the pupil to observe the temperature
difference.
●
Pupils should feel the effect of the liquid evaporating
from the skin.
●
By asking what is happening, find out whether pupils
know the word ‘evaporation’, and what it means.
© Harcourt Education Ltd 2004 Catalyst 2
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Equipment
surgical spirit or ethanol, electric fan
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I6
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Plenaries
Word game
p
?
t
u
^ _
UG LP
TN
Convection
Teacher sheet
C
onduction is how heat travels.
The
O
pposite to a conductor is an insulator.
I
N
sulation stops heat escaping.
Energy can flow in any
D
irection.
Houses need good ins
U
lation.
Ironing clothes needs good
C
onduction of heat.
Me
T
als are the best conductors.
A
I
r is a good insulator.
O
nly a vacuum is better.
N
g from one particle to the next.
The energy is passed alo
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Print Lesson I7 Evaporation, radiation (18 pages)
Evaporation, radiation
I7
M
6
Plenaries
Suggested alternative plenary activities (5–10 minutes)
p
?
t
u
Review learning
Sharing responses
Group feedback
Word game
Looking back
Wordsearch and definitions
from unit.
Whole-class discussion of
Activity I7a.
In groups, use observations
from Activity I7b to debate
whether heaters should all
be painted black.
Match up the beginnings
and endings of sentences
about evaporation and
radiation.
Pupils revise and
consolidate knowledge from
the unit.
^ _
UG LP Review learning
●
Ask pupils to complete the wordsearch on the pupil
sheet.
●
Ring the words on a copy of the pupil sheet and show
it as an OHT for them to check their answers. Use the
words on it to introduce the lesson.
➔ Pupil sheet
Sharing responses
●
Ask volunteers to describe what they observed in
Activity I7a. Then ask for other volunteers to explain
why this happened in terms of particles.
Group feedback
●
Explain that most heaters, including so-called radiators,
are convectors not radiators.
●
In groups, pupils use their observations from Activity
I7b to consider whether all ‘radiators’ should be painted
black.
●
Then collate their views on the board. Black is best as it
radiates most heat – so heaters would be more efficient,
but there are aesthetic considerations too.
Word game
●
Pupils match up the beginnings and endings of
sentences so that each statement is an observation
followed by a sensible qualifier/explanation.
●
The cards could also be used as a loop game.
➔ Pupil sheet
Looking back
●
Pupils revise and consolidate knowledge from the unit.
They can use the Unit map, Pupil checklist, or the Test
yourself questions.
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
➔ Unit map
➔ Pupil checklist
➔ Test yourself
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I7
M
p
t
Evaporation, radiation
Plenaries
Review learning
?
All these words are connected with heat. See how many of them you
u can find in the wordsearch.
^ _ If you have time, write a clue for each word to help someone guess
UG LP
TN
what words are in the wordsearch.
particle
temperature
conduction
Celsius
thermal
insulate
thermometer
condensation
boiling
Joules
evaporation
radiation
expansion
current
convection
heating
cooling
melting
t
e
m
p
e
r
a
t
u
r
e
p
t
w
h
e
l
c
i
t
r
a
p
h
o
q
u
x
e
n
c
o
n
d
u
c
t
i
o
n
v
y
r
o
u
n
c
u
r
r
e
n
t
o
c
z
m
i
v
v
x
e
x
p
a
n
s
i
o
n
o
t
h
e
r
m
a
l
f
i
l
t
o
g
m
a
r
c
e
l
s
i
u
s
m
a
l
n
e
r
m
t
e
t
a
l
u
s
n
i
i
i
t
o
t
i
y
a
c
r
a
w
e
d
n
t
e
p
j
o
u
l
e
s
g
j
n
a
g
l
r
a
w
n
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n
i
t
a
e
h
r
e
e
s
v
b
o
i
l
i
n
g
k
o
r
s
m
t
e
c
o
n
d
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n
s
a
t
i
o
n
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Print Lesson I7 Evaporation, radiation (18 pages)
I7
M
Evaporation, radiation
Word game
p
?
t
u
^ _
Beginnings
Endings
A vacuum …
… of heat transfer that can
get through a vacuum.
Radiation is the only
form …
… has no particles in it at
all.
A shiny silver surface is the
best …
… the draught carries the
particles away.
A dull black surface is the
worst …
… break the bonds between
the particles in a liquid.
Evaporation is when a
liquid …
… reflector of heat
radiation.
Evaporation causes cooling
because it takes energy
from the surroundings to …
… because there is more
surface area for the particles
to escape from.
Evaporation happens faster
in a flat open dish …
… reflector of heat
radiation.
Evaporation happens faster
in a draught because …
… turns to a gas, without
boiling.
UG LP
TN
Plenaries
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Explaining the results –
Think about
I8
6
Plenaries
M
p
?
Suggested alternative plenary activities (5–10 minutes)
t
u
Group feedback
Bridging to other topics
Highlight the importance of identifying all
the variables in an investigation and
controlling some of them.
Give pupils examples of other things that
are affected by more than one
independent variable and ask them to say
what the variables are.
^ _
UG LP
Group feedback
●
Pupils work in groups on an explanation of why it is
important to identify all the variables in an
investigation. For instance in an experiment to find out
whether dissolving salt in water makes it evaporate
more, what would be the variables?
●
Then ask pupils to decide how they could control each
independent variable. If there is time, pupils could
design the experiment, drawing apparatus and planning
how to obtain evidence.
●
Ask for volunteers from each group to share what they
have discussed and summarise for the whole class.
Bridging to other topics
●
Give groups of pupils one or two of the examples
opposite of things that are affected by more than one
independent variable. Ask them to say what the
variables are.
●
Ask for volunteers from each group to share what they
have discussed and summarise for the whole class.
© Harcourt Education Ltd 2004 Catalyst 2
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Examples
density, speed, how fast an animal can run,
pulse rate, number of rabbits on the
common, how quickly sugar dissolves in a
drink, the size of a Bunsen burner flame,
the heat energy given out by burning fuel,
the brightness of bulbs in a circuit
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Print Lesson I7 Evaporation, radiation (18 pages)
I1
M
W
p
?
t
u
^ _
UG LP
A
What temperature?
Specials
1 Tick the boxes to show the right answers.
a To measure temperature I use a:
voltmeter
thermometer
ammeter.
b Temperature is measured in:
degrees Celsius
meters
cubic centimetres.
c Temperature is measured in:
m
cm3
ºC.
d The scientific name for heat is:
sound energy
electrical energy
thermal energy.
2 Use words from this list to fill in the gaps. You may
use words once, more than once or not at all.
electric
al
0 ºC
therma
l
into
a Things feel hot because
moves
out of
sound
energy
my skin.
b Things feel cold because
moves
37 ºC
100 ºC
energy
my skin.
c Water boils and condenses at
d Water freezes and melts at
© Harcourt Education Ltd 2004 Catalyst 2
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.
.
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Print Lesson I7 Evaporation, radiation (18 pages)
I1
M
W
p
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t
u
Specials
What temperature? (continued)
3 Look at this drawing of a thermometer.
110
100
^ _
90
UG LP
80
A
70
60
50
Temperature
40
in °C
30
20
10
0
– 10
– 20
a Label these temperatures in the boxes on the
thermometer.
Human Freezer
body
Temperature
(ºC)
37
−20
Ice
Hot
bath
0
53
Boiling Fridge
water
100
4
b Which temperature is the coldest?
c Which temperature is the hottest?
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Print Lesson I7 Evaporation, radiation (18 pages)
I2
M
W
p
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Temperature and energy
Specials
1 Draw lines to match the sentence beginnings to their
endings.
^ _
…
Temperature is
measured in …
UG LP
the temperature.
A
The energy per
particle is …
Smaller, hotter
things can have less
energy than …
…
larger, colder things.
…
degrees Celsius (ºC).
2 Look at these pairs of drawings.
Which one of each pair has the most energy?
Draw a circle around it.
A
B
30 °C
30 °C
C
50 °C
75 °C
30 °C
25 °C
D
10 °C
10 °C
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Print Lesson I7 Evaporation, radiation (18 pages)
I3
M
W
p
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^ _
Bigger and smaller
Specials
1 Use these words to fill in the gaps. You may use words once,
more than once or not at all.
expand
vibrate
apart
r
e
h
t
r
fu
cont
stop
ract
closer t
ogethe
r
UG LP
A
a Solids and liquids
when heated. The particles
more and take up more space.
b Solids and liquids
when cooled. The particles
less and take up less space.
c Gases
when heated. The particles move
and take up more space.
d Gases
when cooled. The particles move
and take up less space.
2 The first drawing shows the wires between pylons on a cold day.
winter
summer
Complete the second drawing to show the wires on a hot summer’s day.
3 Look at these pictures of gas filled balloons.
a Which balloon is in a
freezer?
b Which balloon is in a
hot room?
c Which balloon is in a
cool room?
A
© Harcourt Education Ltd 2004 Catalyst 2
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B
C
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Print Lesson I7 Evaporation, radiation (18 pages)
I4
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All change
Specials
1 Look at this diagram showing the changes of state.
^ _
UG LP
A
solid
liquid
gas
a Use these words to label the diagram.
boiling
freezin
g
melting
conden
sing
b Colour in red the changes that need heat to happen.
c Colour in blue the changes that need cooling to
happen.
2 Tick the boxes to show the right answers.
a The melting point of a substance is the temperature
where it:
boils and freezes
melts and freezes
condenses and freezes.
b The boiling point of a substance is the temperature
where it:
boils and condenses
melts and boils
freezes and condenses.
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Print Lesson I7 Evaporation, radiation (18 pages)
u
^ _
UG LP
A
Use these words to fill in the labels.
boiling point
...........................
melting
point
..............................
Temperature
in °C
liquid
..............................
...........................
solid
...........................
gas
Energy
4 This graph shows the temperature change as a
gas is cooled.
Use these words to fill in the labels.
melting
point
boiling point
solid
liquid
...........................
Temperature
in °C
..............................
t
..............................
?
..............................
p
3 This graph shows the temperature change as a
solid is heated.
..............................
W
..............................
M
Specials
All change (continued)
..............................
I4
...........................
gas
...........................
Energy
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Print Lesson I7 Evaporation, radiation (18 pages)
I5
M
W
p
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Conduction
Specials
1 Draw lines to match the words to the sentences.
These conduct thermal
energy well.
conduction
^ _
UG LP
A
thermal
conductors
These are poor conductors
of thermal energy.
thermal
insulators
Energy passing along a solid from
the hotter end to the cooler end.
2 Write true or false for each sentence.
a Thermal energy moves from the cooler parts of a
solid to the hotter parts.
b Conduction works better in solids than in liquids or
gases.
c Conduction does not work in a vacuum.
3 Look at these items.
expanded
polystrene cup
cling film
water
cooking foil
air
saucepan
vacuum flask
a Colour the thermal conductors in red.
b Colour the thermal insulators in blue.
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I6
M
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p
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^ _
Convection
Specials
1 Use these words to fill in the gaps. You may use words
once, more than once or not at all.
solid(s)
UG LP
therma
l
liquid(s)
gas(es)
falls
A
rises
current
sound
a Convection happens in
and
but not in
.
b Convection transfers
energy.
c A convection
happens when one
part of the
or
is
hotter than another part.
d In convection, the hotter liquid or gas
and the cooler liquid or gas
.
2 Some purple dye is put into a beaker of water.
A Bunsen burner heats one corner of the beaker.
A
dye
B
dye
C
dye
Which picture shows what happens to the dye?
3 Write true or false for each sentence.
a Hot air falls and cool air rises.
b Thermal energy can be transferred through solids
by convection currents.
c Hot water rises, cold water falls.
d Thermal energy can be transferred through liquids
and gases by convection currents.
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Print Lesson I7 Evaporation, radiation (18 pages)
I7
M
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p
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t
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Evaporation, radiation
Specials
1 Draw lines to match the words to the sentences.
evaporation
When a liquid turns to a gas by
taking in energy from around it.
radiation
This is given out by any
hot object. It acts like light.
^ _
UG LP
A
Thermal energy can be
transferred by ...
infrared radiation
2 When I sweat, it helps to cool me down.
This is because:
Tick the box
to show the
right answer.
sweat is colder than my body
the energy to turn the liquid sweat
into gas is taken from my body
the sweat gives energy to my body
as it turns into a gas.
3 Sometimes a special light bulb is used to keep
chicken eggs warm to help the chicks grow and
hatch from them.
Heat energy is transferred from the
bulb to the eggs by:
conduction
radiation
Tick the box
to show the
right answer.
convection.
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Print Lesson I7 Evaporation, radiation (18 pages)
I7
M
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Evaporation, radiation (continued)
Specials
4 The drawings show thermal energy being transferred
in different ways.
electric bar heater
fan heater blowing hot air
radiator
saucepan on electric hob
^ _
UG LP
A
a Colour in green the picture(s) that show(s)
convection.
b Colour in red the picture(s) that show(s)
radiation.
c Colour in blue the picture(s) that show(s)
conduction.
You may want to use more than one colour
on some of the pictures.
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Print Lesson I7 Evaporation, radiation (18 pages)
I8
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Explaining the results
Specials
1 Sean and Ellen heated three blocks of metal by 40 ºC.
The energy needed to increase their temperature by
40 ºC was measured. Each block weighed 100 g.
Here are the results.
^ _
UG LP
A
Metal (100 g)
Aluminium
Tin
Copper
360
860
1550
Energy needed to raise
temperature by 40 ºC (kJ)
a Show this information as a bar graph
on the grid opposite.
b Which metal needed the most energy
to increase its temperature by 40 ºC?
1600
1500
1400
1300
c This experiment was a fair test. Look
at the list below. Tick all the correct
reasons why it was a fair test.
The metal blocks were
different masses.
The temperature was
raised by the same
amount for each metal.
A different temperature rise
was used for each metal.
The metal blocks were the
same masses.
d To heat the same mass of copper by
the same temperature rise as
aluminium, you would need:
more energy
less energy
the same amount
of energy.
© Harcourt Education Ltd 2004 Catalyst 2
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1200
1100
1000
900
800
Energy 700
in kJ
600
500
400
300
200
100
0
Tin
Aluminium
Copper
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Print Lesson I7 Evaporation, radiation (18 pages)
Heating and cooling
I
?
t
u
^ _
UG
I4 All change
1 a
b
c
d
2 a
b
c
d
3 a
1 a
thermometer
Degrees Celsius.
ºC
Thermal energy.
thermal, into
thermal, out of
100 ºC
0 ºC
From top to bottom – boiling water, hot
bath, human body, fridge, ice, freezer
b freezer
c Boiling water.
I2 Temperature and energy
1 Temperature is measured in degrees Celsius (ºC).
The energy per particle is the temperature.
Smaller, hotter things can have less energy than
larger, colder things.
2 a Circled – left beaker.
b Circled – right beaker.
c Circled – right cube.
d Circled – left cube.
gas
solid
liquid
freezing
condensing
b
c
2 a
b
3
Coloured red – melting, boiling
Coloured blue – condensing, freezing
Melts and freezes.
Boils and condenses.
gas
I3 Bigger and smaller
1 a
b
c
d
2
boiling
melting
Temperature in °C
p
I1 What temperature?
expand, vibrate
contract, vibrate
expand, further apart
contract, closer together
boiling
point
melting
point
liquid
solid
Energy
4
winter
boiling
point
summer
3 a B
b C
c A
Temperature in °C
M
Specials answers
gas
melting
point
liquid
solid
Energy
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Print Lesson I7 Evaporation, radiation (18 pages)
I
p
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u
^ _
UG
I5 Conduction
I8 Explaining the results
1 conduction – Energy passing along a solid from
the hotter end to the cooler end.
thermal conductors – These conduct thermal
energy well.
thermal insulators – These are poor conductors
of thermal energy.
2 a false
b true
c true
3 a Coloured red – cooking foil, saucepan
b Coloured blue – expanded polystyrene cup,
cling film, water, air, vacuum flask
1 a
I6 Convection
1 a
b
b
d
2 C
3 a
b
c
d
liquids, gases, solids
thermal
current, liquid, gas
rises, falls
false
false
true
true
I7 Evaporation, radiation
1 evaporate – When a liquid turns to a gas by
taking in energy from around it.
infrared radiation – This is given out by any hot
object. It acts like light.
Thermal energy can be transferred by …
– infrared radiation.
2 The energy to turn the liquid sweat into gas is
taken from my body.
3 radiation
4 a Coloured green – bar heater, fan heater,
radiator, saucepan
b Coloured red – bar heater, radiator, electric
hob
c Coloured blue – saucepan
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1600
1500
1400
1300
1200
1100
1000
900
Energy in kJ
M
Specials answers
Heating and cooling (continued)
800
700
600
500
400
300
200
100
0
Copper
Tin
Aluminium
b copper
c Ticked – The temperature was raised by the
same amount for each metal. The metal
blocks were the same masses.
d More energy.
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What temperature?
I1
M
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p
?
Homework
A
1 a The diagrams show some
thermometers. Write down the
t u
temperature shown on each
^ _
thermometer.
c
When would you use a
thermometer like the one
shown in diagram E ?
C
C
110
110
110
100
100
100
90
90
90
80
80
80
70
70
70
60
60
60
50
50
50
40
40
40
30
30
30
20
20
20
10
10
10
5
5
5
0
0
0
–5
–5
–5
d In thermometer B, what is
transferred to the thermometer
to make the mercury rise?
D
60 80
10
0
0 20
40
E
140 1
60
120
Copy and complete the
following sentences:
i 100 °C is the ...
ii Water freezes at ...
–20
e
0
–4
0
A
b Where would you be most likely
to find a thermometer like the
one shown in diagram A ?
C
C
18
UG LP
B
31 32 33 34 35 36 37 38 39 40
°C
CORE
2 Sahira’s fridge is cold on the inside. On the outside, at the back,
there is a panel that feels warm.
a What sort of energy has been transferred out of the fridge?
b Explain why the fridge is cold inside but warm outside.
3 Rewrite the following incorrect sentences correctly. You must not
change the underlined sections.
a When I am having a hot bath, thermal energy transfers from
my body to the hot water.
b Water in an electric kettle gets hot because thermal energy is
transferred into the element from the water.
4 a Which is colder, a gas at – 143 °C or a gas at – 245 °C?
b Explain your answer.
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I1
What temperature? (continued)
M
W EXTENSION
p
?
t
5 Remember that, on the Kelvin temperature scale, the lowest
possible temperature is 0 K (nought degrees Kelvin). This is the
u
same as –273 °C on the Celsius scale.
^ _
UG LP
A
Homework
a On the Kelvin scale what is:
i the boiling point of water?
ii the freezing point of water?
iii the melting point of lead (which is 328 °C)?
iv the difference between the freezing point of water and the
boiling point of water?
b i What do scientists call the lowest possible temperature?
ii Explain why it is impossible for anything to be colder than
this temperature.
c
i
The temperature of a plumber’s blowtorch flame is about
1773 K. Why is lead a good metal to put into the solder
that plumbers use to join pipes together?
ii Water pipes are usually made from copper. What must be
the lowest possible melting point of copper, given that the
pipes do not melt when plumbers use a blowtorch on
them?
6 The diagram shows a metal cube filled with hot water at 60 °C.
Ed touches the sides to find out if the surfaces feel the same.
120
110
100
90
thermometer
80
70
60
50
40
30
20
10
metal cube
filled with water
a All the sides feel warm. Using ideas about energy transfer,
explain why Ed’s hands feel warm when he touches the sides
of the cube.
b After thirty minutes, the water inside the cube is at the same
temperature as the air outside it. Explain why this has
happened.
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Temperature and energy
I2
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Homework
1 Write down the following in the order in which they would boil.
Put the quickest first. Use the letters for your answer:
^ _
A a half-full kettle of water.
UG LP
B a half-full bath of water.
A
6
C a full kettle of water.
D a full bucket of water.
E
a swimming pool full of water.
2 Tom puts one litre of water, at 20 °C into a kettle and heats it up.
After three minutes the temperature is 57 °C.
He repeats the experiment with a different amount of water. This
time, the temperature rises to 74 °C in three minutes.
a Why did Tom heat both of them for three minutes?
b What was the rise in temperature in the first experiment?
c
What was the rise in temperature in the second experiment?
d i
Did Tom use more water or less water in the second experiment
than in the first?
ii Explain how you reached your answer.
CORE
3 a Write down the following in their order of energy content. Start with
the one that contains the least energy. Use the letters for your answer:
A 10 cm3 of water at 10 °C.
B 100 cm3 of water at 99 °C.
C 100 cm3 of water at 10 °C.
D 100 cm3 of water at 50 °C.
E
10 cm3 of water at 5 °C.
b Explain why 1 kg of solid gold contains less energy than 1 kg of liquid gold.
c
1 g of iron, at 20 °C, contains less energy than 1 g of water at 20 °C.
Explain what this tells you about the number of particles in 1 g of water
compared with the number of particles in 1 g of iron.
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I2
Temperature and energy (continued)
M
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p
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Homework
4 Reptiles need to warm up their blood, before they can become really active, by lying
in the sun. The bigger the reptile, the longer it needs to lie in the sun before it feels
u
active enough to hunt.
^ _
UG LP
A
6
a Explain why a snake with a mass of 1500 g must lie in the sun longer than
another snake with a mass of 500 g.
b In the UK, the only poisonous snake is the adder. You are much more likely to be
bitten by an adder in the afternoon than early in the morning. Explain why.
c
Some lizards can flatten out their bodies, when they lie in the morning sun.
Explain how this helps these lizards to warm up quickly.
5 Fire fighters often extinguish fires with water. This not only puts out the flames but it
also cools the burning material.
Two fire crews are tackling fires in separate wood yards. Crew A are fighting a fire
where there are 15 000 kg of wood on fire. In Crew B’s fire there are 1000 kg of wood
burning.
a i Which fire crew would need to use the most water?
ii Explain your answer in terms of energy.
b In terms of the fire triangle, which aspect of the triangle have the fire crews
removed when they put out the fire?
6 Look at the data in the table below. It shows the final temperature reached when a
substance from column 1 was mixed with a substance from column 2 in an insulated
container.
Column 1
Column 2
Final temperature
of the mixture
X
100 cm3 of water at 25 °C
36 °C
Y
1000 cm3 of water at 25 °C
74 °C
Z
100 cm3 of water at 25 °C
58 °C
a i Which of the lettered substances X, Y and Z contained the most energy?
ii Explain your answer.
b i
What would happen to the final temperature reached, for substance X, if the
same amount of X was put into twice the volume of water?
ii Explain why this would happen.
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Bigger and smaller
I3
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a When a substance contracts it …
^ _
b When a substance is heated it …
UG LP
c
A
6
Homework
1 Copy and complete the following sentences:
When a liquid is heated the particles …
d When a gas is heated the gaps between the particles …
2 The Eiffel tower, in Paris, is about 300 m high. It is taller in the
summer than in the winter.
a Write a sentence to explain why the tower is taller in the
summer.
b Sometimes, on a cool summer evening, you can hear the
Eiffel tower creaking. Write a sentence to explain what makes
it creak.
CORE
3 a Copy and complete the table below, about the particles in
some copper. All four samples contain the same mass of
copper.
Material
Physical
state
Nature of the particles
Amount of energy
in material
Cold
copper
Solid
All touching in a regular
arrangement and vibrating
a little.
Low
Hot
copper
A
All touching in a regular
arrangement and vibrating
very fast.
B
Copper
Gas
C
Very high
Copper
Liquid
D
High
b Explain how the nature of the particles in the solid copper
samples affects the volume of the samples.
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I3
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A
Homework
Bigger and smaller (continued)
c
Water pipes are usually made from copper. Sections of pipe
are held together with solder, which can stretch without
cracking. Explain why the solder in the pipes in a central
heating system must be able to stretch.
d The diagram shows
a metal bridge
across a river. It was
built with a gap at
one end.
Explain why there is
a gap in December
but not in July.
gap left
by builder
concrete span
bridge pillar
EXTENSION
4 John warms a large flask, as shown
in the diagram.
a Explain why John sees bubbles
coming out of the tube.
b i
What will happen if he
removes his hands from the
flask but leaves the tube in
the water?
Beaker of
ii Explain why this will
water
happen.
Large flask
filled with air
clamp
5 a Calculate the densities of the
following materials:
i a piece of lead having a mass of 22.6 g and a volume of
2 cm3.
ii a block of iron having a volume of 200 cm3 and a mass of
1580 g.
b i
Calculate the volume of a piece of copper having a mass
of 450 g and a density of 8.9 g/cm3.
ii Explain what will happen to the number of particles and
the volume they occupy, if the piece of copper is heated.
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All change
I4
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Homework
1 Copy and complete the diagram below, filling in the spaces. Use only
words from the list.
^ _
condensing
UG LP
liquid
freezing
boiling
melting
A
gas
solid
2 a Use the data in the table below to draw a graph. You will need
some graph paper.
Time in minutes
0
1
2
3
4
5
6
7
8
Temperature in °C
30
28
26
25
24
24
24
24 23
b The substance was a liquid at the start. What is happening to its
state between 4 minutes and 7 minutes?
c
What is different about the particles in the substance at 8 minutes
compared with at 1 minute?
CORE
3 a Look at the data given for question 2a. Sketch the shape of the
graph you would obtain if you had started with the substance at
23 °C and heated it up to 30 °C.
b Explain how the arrangement of the particles would change if
you continued to heat the substance until it became a gas.
c
Explain what is happening to all the energy you put into the substance.
EXTENSION
4 a Explain, in terms of changes of state, what scientists mean when they
talk about a reversible process.
b i
Sketch the shape of the graph you would expect to obtain if you
heated some ice, at −10 °C until it had all become steam at 110 °C.
ii Explain the shape of graph that you have drawn.
c
First aid books often say that a burn from steam at 100 °C is much
worse than a burn from boiling water at 100 °C. Using your
knowledge of particles and energy, explain why this is true.
d Describe how the forces of attraction between water molecules
change as it condenses from steam to liquid water.
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Conduction
I5
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^ _
UG LP
A
Homework
1 Sam’s granddad has made a cup of tea in a plastic mug. He left the metal
spoon in the tea while he answered the telephone.
Write sentences about conduction to explain each of the following
observations:
a The spoon was hot when Sam’s granddad came back from the
telephone.
b The mug handle was not hot after the telephone call.
c
The metal spoon cooled down quickly when cool water was run onto it.
d Sam’s grandma’s mug, made from metal, burned her lips when she
tried to drink her tea from it.
2 a Sam wanted to find out more about conduction. She made three cubes.
The first was made from solid copper. The second was a copper box
filled with water. The third was a copper box filled with air.
Sam put the same Bunsen
flame underneath each
box. She put a
thermometer above each
box. She heated each box
for 5 minutes.
Copy and complete the
following sentences:
i The thermometer
that reached the
highest temperature
was the one above
the solid copper box
because …
ii The thermometer
above the air-filled
box hardly warmed
up at all because …
160
150
160
150
160
150
140
130
120
110
100
90
80
140
130
120
110
100
90
80
140
130
120
110
100
90
80
70
60
50
40
30
20
15
70
60
50
40
30
20
15
70
60
50
40
30
20
15
10
5
0
10
5
0
10
5
0
solid copper
cube
water-filled
copper cube
air-filled
copper cube
b Normal double-glazing is made from two layers of glass with air trapped
in between them. Complete the following sentence:
Normal double-glazing helps to keep houses warm because …
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I5
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UG LP
A
Homework
Conduction (continued)
3 a Loft insulation is a loose fibre roll that traps heat inside the house. Explain why it
traps heat in the house.
b Hot water cylinders in new houses are surrounded by a thick layer of polystyrene
foam. What property does the polystyrene foam have?
4 Joel set up an experiment like the one shown in the
diagram.
metal rod
clamp
10 cm
He used five different rods, all the same length.
He heated the rods and timed how long it took
for the drawing pin to drop off. He recorded his
results in the table shown below.
drawing pin
petroleum
jelly
Rod
Copper
Iron
Glass
Aluminium
Graphite
Time for pin
to drop off (s)
23
79
650
26
207
a Which material is the best conductor of heat?
b Which material is the worst conductor of heat?
c
The experiment shows that some solids conduct heat much better than others.
Using a particle model, explain why all solids conduct heat better than gases.
EXTENSION
5 a Using ideas about particles, explain how the heat from a cup of coffee transfers to
the end of a spoon held in your hand, when you are stirring the coffee.
b Explain why the heat of the sun cannot possibly reach the Earth by conduction.
c
Fred is a farrier. He shoes horses. He cools his horseshoes by putting them into a
tank of cold water, after they have been in the furnace. Each horseshoe comes out
of the furnace at about 1000 °C. The water temperature rises by about 1 °C every
time he puts a hot shoe into it.
i Explain why the horseshoe cools by over 900 °C but the water temperature
only rises by a few degrees.
ii Explain why the shoe would cool much more slowly if Fred just held it in the
air to cool.
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Print Lesson I7 Evaporation, radiation (18 pages)
Convection
I6
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Homework
1 a Complete the wordsearch by finding the following words
about heat. You will need a copy of the wordsearch on
u
sheet 3.
^ _
n
conductio
UG LP
A
particles
temperatu
re
current
transfer
convectio
n
thermal
b Write down the word in the list that is about heat transfer
when the heat moves along an object.
c
Write down the two words that go together to describe the
way heat is transferred through liquids and gases.
d Write down the word that means the same as heat.
e
Write down the word that is something you can measure to
show how hot a substance is.
CORE
2 a Write a couple of sentences to explain how thermal energy
from a radiator reaches the other side of a room.
b Gliders use convection currents to gain height. If there are
no convection currents the glider will descend. Explain why
gliders rise when over a town.
c
Sea breezes are caused by convection currents. They
sometimes cause a cool breeze to blow in off the sea. Copy
the diagram below and then add arrows to show how
convection currents could be caused by warm air rising over
the land.
land
sea
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Print Lesson I7 Evaporation, radiation (18 pages)
I6
6
Convection (continued)
M
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p
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Homework
3 The diagram shows a hot air balloon with its
pilot. The pilot controls the height of the
t u
balloon by turning a gas burner on and off.
^ _
If he wants to go up, he turns the burner on.
He turns it off to descend.
UG LP
A
a Explain why the pilot must ignite the
burner to ascend.
b To keep the balloon at a constant height,
the pilot gives occasional blasts on the
burner. Why must he do this?
c
If the pilot wants to descend quickly he can
pull a cord to create a hole in the top of the
balloon. Explain why this speeds up his
descent.
d When he is setting off the pilot must first inflate the balloon.
He does this by having a ground crew hold the bottom of the
balloon wide open. Then he points his burner into the hole
they have made. Slowly, the balloon inflates.
Explain why directing the burner into the hole created by the
ground crew inflates the balloon, when all the pilot is doing is
heating up the air that is inside it.
4 It is bonfire night and Zena and her friends are having a bonfire
party. Zena notices that the smoke from the fire is rising very
quickly. She knows that smoke is tiny particles of soot. Describe
what you would say to her to explain how these particles are
being made to rise so quickly.
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I6
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Homework
Convection (continued)
Wordsearch for question 1
T
P
U
P
Y
E
F
L
C
N
E
F
E
Z
O
A
P
L
A
M
R
E
H
T
M
A
L
R
J
W
E
I
P
U
P
N
P
C
O
T
U
C
D
I
O
N
T
O
E
U
A
I
Y
H
Q
D
O
R
G
I
R
R
P
C
E
K
D
G
A
R
M
T
A
R
B
L
M
H
W
N
F
M
R
C
T
E
E
E
T
S
S
Q
E
Y
R
E
U
N
E
S
C
F
M
T
E
A
M
V
R
T
A
L
E
U
A
L
S
E
O
N
E
V
E
R
D
V
E
N
F
U
I
O
V
E
N
O
I
T
C
U
D
N
O
C
^ _
UG LP
A
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Print Lesson I7 Evaporation, radiation (18 pages)
6
Evaporation, radiation
I7
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Homework
1 Look at the diagrams. They all show a use
A
of either evaporation or radiation. Write
t u
two headings ‘Evaporation’ and ‘Radiation’
^ _
in your book and write each of the letters
Paint drying
from the diagrams under the correct heading.
UG LP
C
2 James has a dish containing some copper
A
sulphate solution. He wants to grow some
Washing out on
crystals of copper sulphate. To do this he
a windy day
must evaporate some of the water from the
E
solution.
a James decides to warm the solution.
He uses a Bunsen burner with the air hole
half open. Explain why this will help him
to get some crystals quickly.
B
Infrared heater for
chicks
D
Jemma
sunbathing carefully
Kebab cooking on a
grill
b James thinks that his evaporation is a bit slow, so he fully
opens the air hole on his Bunsen burner. Write a sentence
to explain why this speeds up the evaporation.
CORE
3 Pedro is a painter and decorator. He cleans his brushes in a
special brush-cleaning fluid. If he spills some on his hands they
feel very cold as they are drying off.
a Using ideas about energy movement, explain why Pedro’s
hands feel cold when he spills brush cleaner onto them.
b The brush cleaner dries off faster on Pedro’s hands than it
does if he spills some on his painter’s apron. Explain why.
4 Jasmine is sitting in her room. She has her central heating radiator
on but is still feeling cold. She turns on her electric bar fire. She
can feel the heat from the electric bar fire coming straight at her.
She cannot feel the heat from the radiator in the same way.
a How is the thermal energy from the radiator being transferred
to Jasmine?
b How is the heat from the electric bar fire being transferred to
Jasmine?
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6
Evaporation, radiation (continued)
c
Homework
i
Which of the heaters might cause Jasmine’s skin to burn,
as it would if she stayed in the sun for too long?
ii Explain how you chose your answer.
d i
Which of the heaters would be able to transfer thermal
energy if it were used on the Moon?
ii Explain why only this heater would work on the Moon.
iii Scientists have observed that the temperature on the
Moon’s lit side is high but the temperature on its dark side
is very low. Explain this observaton.
UG LP
A
EXTENSION
5 a When young children have a fever their skin becomes very
hot. Parents say that they are ‘burning up’. Suggest where the
thermal energy, that makes their skin so hot, has come from.
b Suggest how this thermal energy reaches the skin.
c
One way to help the sick child is to remove their clothes,
sponge them with tepid (slightly warm) water and leave them
to dry in the air. Explain how ‘tepid sponging’ will help to
lower their temperature.
d Dr Turner took an infrared photograph of a child with a fever
and compared it with a similar child who did not have a
fever. Describe how the two photographs would be different.
6 Some young people are doing a sponsored walk across some
mountains in the Lake District. One of them is injured and a walk
official tries to prevent the walker from getting too cold while the
mountain rescue team arrives. The mountain rescue doctor
covers the casualty with a bubble-wrap layer and then with a
shiny silver survival blanket.
a What thermal energy transfer processes would have caused
the walker to cool down too much?
b How could the walk official have prevented this from
happening?
c
Why did the doctor use a bubble-wrap layer first?
d How could the shiny survival blanket help to keep the
casualty warm?
© Harcourt Education Ltd 2004 Catalyst 2
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Print Lesson I7 Evaporation, radiation (18 pages)
What temperature?
I1
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HM
6
Homework
mark scheme
Question
Answer
1
A = 97 °C; B = 34 °C; C = −5 °C; D = 25 °C (Accept 20–30) ; E = 37 °C
One mark for each correct temperature plus 1 mark if units included at least once.
6
b
In a science lab.
1
c
To take a child’s/person’s temperature or on a fish tank.
1
d
Thermal energy. Accept ‘heat’.
1
e i
100 °C is the boiling point of water. Underscore shows the pupil response.
1
Water freezes at 0 °C. Underscore shows the pupil response.
1
a
ii
Mark
Total for Help
11
CORE
Question
Answer
2 a
Thermal energy. Accept ‘heat’.
1
There is less thermal energy inside the fridge than outside it because the fridge
has transferred the energy to the panel at the back. Accept equivalent answers.
1
1
When I am having a bath, thermal energy transfers from the water to my body.
Underscore shows the pupil response.
1
Water in an electric kettle gets hot because thermal energy is transferred from
the element into the water. Underscore shows the pupil response.
1
The gas at –245 °C is colder.
1
The Celsius scale goes downwards from zero/they are negative numbers.
Accept equivalent answers.
1
b
3 a
b
4 a
b
Mark
Total for Core
7
EXTENSION
Question
Answer
5 a i
373 K
1
ii
273 K
1
iii
601 K
1
iv
100 K
1
Absolute zero.
1
All the energy has gone at absolute zero.
1
It melts easily.
1
1774 K/Above 1773 K. Accept equivalent answers.
1
Thermal energy from the water
flows evenly through the metal sides
into Ed’s hand, warming it up.
1
1
1
Some of the energy inside the cube, which made it hot, has transferred to the
air outside the cube.
Now each particle inside the cube has the same amount of thermal energy
as each particle outside
so the temperatures are the same.
1
b i
ii
c i
ii
6 a
b
Mark
Total for Extension
© Harcourt Education Ltd 2004 Catalyst 2
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1
1
14
Sheet 1 of 7
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Print Lesson I7 Evaporation, radiation (18 pages)
Temperature and energy
I2
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HM
6
Homework
mark scheme
Question
Answer
1
A somewhere before C. C somewhere before D. D somewhere before B.
B somewhere before E. One mark for each correct answer.
4
2 a
To make it a fair test.
1
b
37 °C
2
c
54 °C
1
d i
Less
1
The temperature rose further/higher/more
for the same amount of heating.
1
1
ii
Mark
(1 mark for the numerical value; 1 mark for the unit)
Total for Help
11
CORE
Question
Answer
Mark
3 a
E somewhere before A. A somewhere before C. C somewhere before D.
D somewhere before B. One mark for each correct answer.
4
b
Liquid gold must be at a higher temperature than solid gold.
Both have the same number of particles.
So the one at the higher temperature has the most energy.
Accept equivalent answers.
1
1
1
c
Both have the same mass.
So the one with the higher energy must contain more particles (per gram).
Therefore, there are more particles in the water than in the iron.
Accept equivalent answers.
1
1
1
Total for Core
10
EXTENSION
Question
Answer
4 a
The larger snake contains more particles
so must gain more energy to reach the same temperature as the smaller
snake. Accept equivalent answers.
1
1
b
It has not warmed up in the morning so has not the energy to attack.
Accept equivalent answers.
1
c
Flattening out increases their surface area
so they can absorb the sun’s energy faster.
1
1
Crew A.
1
The larger mass of wood contains the most energy
so it needs more water to absorb the energy.
1
1
Heat
1
Y
1
It warms a much larger volume/amount of water to a higher temperature
than the others.
1
The water temperature/it would be lower.
1
The same amount of energy is being absorbed by fewer water particles
so the average energy per particle is greater.
1
1
5 a i
ii
b
6 a i
ii
b i
ii
Mark
Total for Extension
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14
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Print Lesson I7 Evaporation, radiation (18 pages)
M
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p
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u
^ _
Question
Answer
1 a
When a substance contracts it gets smaller. Underscore shows the pupil response.
1
b
When a substance is heated it expands. Underscore shows the pupil response.
1
c
When a liquid is heated the particles vibrate faster
and move around more quickly/with more energy.
Underscore shows the pupil response.
1
1
d
When a gas is heated the gaps between the particles get larger.
Underscore shows the pupil response.
1
In the summer the higher temperature makes the metal/tower expand.
1
As the tower cools it contracts.
The creaking is the joints/rivets suddenly slipping against each other.
1
1
UG LP
HM
Homework
mark scheme
Bigger and smaller
I3
t
6
2 a
b
Mark
Total for Help
8
CORE
Question
Answer
Mark
3 a
The missing responses are: A Hot solid; B High;
C None touching. Vibrating vigorously; D Most touching. But no regular pattern.
1+1
2+2
b
The more they vibrate the more space they take up
so the hotter sample is bigger than the cooler one.
1
1
c
The pipes expand when hot water goes through them
and contract when it does not.
So the solder will get stretched frequently.
1
1
1
d
In December the bridge is cold
so the structure has contracted and is shorter.
In July it has warmed
and expanded to fill the gap.
1
1
1
1
Total for Core
15
EXTENSION
Question
Answer
4 a
His hands warm the air in the flask, which expands
so some of it is pushed out of the tube as bubbles.
1
1
Water will rise up the tube/into the flask.
1
The air contracts as it cools
and only water can take the place of the air that bubbled out.
1
1
11.3 g/cm3 One mark is for the numerical value and one for the unit.
2
7.9 g/cm3
1
b i
ii
5 a i
ii
b i
ii
Mark
1+1
50.6 cm3 Accept answers from 50.5–50.6.
One mark is for the numerical value; the other is for the unit.
The number of particles stays the same.
The volume they occupy increases.
1
1
Total for Extension
© Harcourt Education Ltd 2004 Catalyst 2
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12
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Print Lesson I7 Evaporation, radiation (18 pages)
Homework
mark scheme
All change
I4
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^ _
6
Question
Answer
1
The missing word sequence from the left is: freezing; liquid;
boiling; condensing
4
2 a
Sensible scale.
Axes labelled.
Single line drawn.
Clearly shows ‘flat spot’.
Award a maximum of 2 marks for a bar graph.
1
1
1
1
b
It is freezing/solidifying/turning into a solid.
1
c
They are closer together/in a regular pattern/all touching/not moving around.
Award 2 marks for two suggestions from the list given above.
2
UG LP
HM
Mark
Total for Help
11
CORE
Question
Answer
3 a
Graph is the reverse of the one plotted for Question 2a.
Award 1 mark for the overall shape and 1 mark for a flat spot at 24 °C.
b
c
Mark
2
They would:
separate from each other.
move around very fast.
1
1
It is separating/breaking apart the particles from each other.
1
Total for Core
5
EXTENSION
Question
Answer
4 a
One that can go in both directions,
such as a liquid becoming a gas, then condensing back to a liquid as it cools.
Accept other correct examples.
1
1
Graph must have: General upward trending line from left to right.
A flat spot at 0 °C.
Another flat spot at 100 °C.
1
1
1
b i
ii
c
d
Mark
Answer must contain:
a reference to the generally increasing energy of the particles raising
the temperature.
an indication that, at the two flat spots, the forces of attraction are being
broken rather than the substance merely being warmed up.
1
1
When steam burns the skin absorbs all the energy that has gone into
separating the particles,
as well as the energy that raised it to 100 °C.
With boiling water, only the energy that raised its temperature to 100 °C
is absorbed
which is significantly less.
1
1
As the steam condenses, forces of attraction between the molecules develop.
These hold the molecules closer together in the liquid.
1
1
1
1
Total for Extension
© Harcourt Education Ltd 2004 Catalyst 2
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13
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Conduction
I5
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6
Homework
mark scheme
Question
Answer
1 a
Sentence must contain reference to the metal being a good conductor of heat.
1
b
Sentence must contain ref to plastic being a poor conductor/good insulator.
1
c
Sentence must contain reference to the heat transferring from the metal to
the water quickly.
1
d
Sentence must contain reference to the metal being a good conductor of heat.
1
The thermometer that reached the highest temperature was the one above the
solid copper box because solids conduct heat faster than liquids or gases.
Underscore shows the pupil response.
1
The thermometer above the air-filled box hardly warmed up at all because
air is a very poor conductor of heat. Underscore shows the pupil response.
1
Normal double-glazing helps to keep houses warm because the air between
the glass panes does not conduct heat very well/is a good insulator.
Underscore shows the pupil response.
1
HM 2 a i
ii
b
Mark
Total for Help
7
CORE
Question
Answer
3 a
There are air pockets inside the fibre roll
which do not conduct heat well
and fibre is also a poor thermal conductor.
1
1
1
The polystyrene foam is a poor conductor of heat. Accept ref to air pockets in foam.
1
Copper.
1
b
Glass.
1
c
Thermal energy is conducted when high energy particles collide with lower
energy ones next to them passing on some of their energy.
Particles in a solid are much closer together than those in gases
so they collide with each other much more often.
1
1
1
1
b
4 a
Mark
Total for Core
10
EXTENSION
Question
Answer
5 a
Heat energy in the vibrating coffee particles is transferred to the metal
when the coffee particles collide with the metal particles.
This makes the spoon particles vibrate more
so they knock into the next ones up the spoon, transferring some of the
thermal energy.
This continues up the spoon to your hand, which detects the thermal energy.
1
b
There is a vacuum between the sun and the earth
and vacuums do not conduct heat
because there are no particles to transfer it.
1
1
1
c i
There are many more particles in the water than in the horseshoe
so the thermal energy in the shoe is much more spread out in the water.
1
1
Air is a poorer thermal conductor than water
so the thermal energy spreads out much more slowly.
1
1
ii
Mark
Total for Extension
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
1
1
1
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6
Homework
mark scheme
Convection
I6
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Question
Answer
1 a
Seven words to be found; see pupil sheet. Deduct 1 mark for each word not found.
5
b
Conduction.
1
c
Convection
current.
1
1
d
Thermal.
1
e
Temperature.
1
^ _
UG LP
HM
Mark
Total for Help
10
CORE
Question
Answer
Mark
2 a
Sentences must include reference to:
hot air above the radiator rising and spreading
cool air in the room falling and replacing the air near the radiator
1
1
b
Towns produce heat.
The air over a town is warmed by the heat
so convection currents are set up
which rise upwards from the town.
The convection currents carry the glider up.
1
1
1
1
1
c
Diagram should contain the following arrows:
Upward arrow(s) over the land.
Downward arrow(s) over the sea.
Arrow showing wind moving from the sea towards the land at sea level.
1
1
1
Total for Core
10
EXTENSION
Question
Answer
3 a
The burners warm the air inside the balloon.
This lowers its density compared with the air outside the balloon.
1
1
b
The density must be kept the same
or the balloon will rise or fall.
1
1
c
The hole provides a route for the warm air to escape from the balloon
so the air inside cools more quickly and the balloon descends faster.
1
1
d
The burner heats the air inside the balloon.
This makes the air particles inside the balloon move faster
so they become less dense
and take up more space.
The balloon must expand to provide the extra space needed by the air particles.
1
1
1
1
1
The fire is heating the air above it.
This creates strong convection currents rising upward.
The currents carry the smoke/soot particles as they rise.
1
1
1
4
Mark
Total for Extension
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6
Homework
mark scheme
Evaporation, radiation
I7
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Question
Answer
1
Evaporation is A and C.
Radiation is B, D and E.
5
Warming gives the water particles more energy
so they move faster and evaporate more quickly.
1
1
The Bunsen flame is now hotter/contains more thermal energy
which makes the water particles move faster
so they evaporate even more quickly.
1
1
1
^ _
2 a
UG LP
b
HM
Mark
Total for Help
10
CORE
Question
Answer
3 a
The cleaner evaporates from his hands
transferring thermal energy away from them as it does so.
1
1
There is more thermal energy in his hands than in his apron
so the cleaner evaporates faster.
1
1
By convection.
1
b
By radiation.
1
c i
The electric bar fire.
1
It produces infrared radiation like the Sun.
1
The electric bar heater.
1
ii
There is no atmosphere on the Moon
so convection could not work/so radiation is the only possibility.
1
1
iii
Radiation travels in straight lines
so cannot get round to the dark side
and there is no atmosphere to transfer heat by convection currents.
1
1
1
b
4 a
ii
d i
Mark
Total for Core
14
EXTENSION
Question
Answer
Mark
5 a
From inside the body.
1
b
It is carried in the blood.
1
c
The thermal energy in their skin is transferred to the water
which evaporates, taking the energy away from their body.
1
1
d
The sick child would have a much brighter image than the well child.
Accept equivalent answers.
1
6 a
Mainly convection of heat from the skin into the air. Accept ‘radiation’.
1
b
Put on more insulating clothing.
1
c
To reduce heat loss due to conduction and convection.
1
d
It reduces heat loss due to radiation.
1
Total for Extension
© Harcourt Education Ltd 2004 Catalyst 2
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9
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Test-Qust.qxd
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Print Lesson I7 Evaporation, radiation (18 pages)
I
M
Heating and cooling
Test yourself
1 Complete these sentences.
p
?
a The instrument used to measure temperature is a
t
u
b The unit used to measure temperature is
^ _
c The boiling point of water is
UG
d The melting point of ice is
A
.
.
.
.
2 Complete these sentences.
Hot food cools down because the
of the food is higher
than room temperature. As a result,
flows from
the food to the surroundings.
3 These four beakers of
water are all at 50 ºC.
Which one will take the
longest to heat up to
100 ºC?
A
B
C
D
4 Write true or false for each statement.
a Temperature and energy are the same thing.
b A small hot thing may contain less energy than a larger cooler thing.
c The hottest thing always contains the most energy.
d Temperature is the amount of energy per particle.
5 Complete these sentences using the words below.
gases
slower
contracts
together
cool
expands
When a metal rod is heated, it
vibrate
faster
. This is because the particles
and so move each other further
the metal rod is allowed to
vibrate
apart
, it
and so they move
. When
. The particles
. Liquids and
expand and contract in the same way.
© Harcourt Education Ltd 2004 Catalyst 2
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Print Lesson I7 Evaporation, radiation (18 pages)
I
M
p
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t
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UG
A
Test yourself
Heating and cooling (continued)
6 These sentences are about changes of state when a substance is heated.
Cross out the wrong words.
a When a solid is heated, its temperature rises/falls/stays constant. At its melting
point it turns to a liquid/gas. During melting, the temperature rises/falls/stays
constant while the particles break apart/join together. When all the substance
is liquid the temperature rises/falls/stays constant.
b A liquid turns to a gas at its freezing point/melting point/boiling point.
During boiling, the temperature rises/falls/stays constant while the particles
break apart/join together. The particles are free to move about in the gas.
7 Here is a list of thermal conductors and insulators.
Underline the conductors. Circle the insulators.
wood
aluminium
polystyrene
copper
rubber
water
air
silver
brass
8 Loft insulation is made from a material that has lots of pockets of trapped air.
It works because air is a good insulator. Without loft insulation, the roof space
is full of air. Why does this not keep the heat in?
9 The diagram shows water being gently heated.
Complete the description of what happens.
When the water is heated, it
and so becomes less
. This causes the water to rise. Cooler water falls
because it is more dense. So
currents are
gentle
heat
set up in the water. In time, it will all be heated to the same
. Convection also happens in
.
10 How does heat reach us from the Sun, by conduction, convection
or infrared radiation?
11 Which is the best explanation for when evaporation occurs?
Circle the correct letter.
A A liquid reaches its boiling point.
B The most energetic molecules escape from the liquid.
C Slow moving molecules escape from the surface of the liquid.
D A liquid gains too little energy.
© Harcourt Education Ltd 2004 Catalyst 2
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Print Lesson I7 Evaporation, radiation (18 pages)
I
M
Test yourself
Answers
Heating and cooling
1 Complete these sentences.
p
?
a The instrument used to measure temperature is a
t
u
b The unit used to measure temperature is
^ _
c The boiling point of water is
100 °C
UG
d The melting point of ice is
0 °C
TY
thermometer
.
°C/degrees Celcius .
.
.
2 Complete these sentences.
temperature
Hot food cools down because the
of the food is higher
thermal energy
than room temperature. As a result,
flows from
the food to the surroundings.
3 These four beakers of
water are all at 50 ºC.
Which one will take the
longest to heat up to
D
100 ºC?
A
B
C
D
4 Write true or false for each statement.
a Temperature and energy are the same thing.
false
b A small hot thing may contain less energy than a larger cooler thing.
true
c The hottest thing always contains the most energy.
d Temperature is the amount of energy per particle.
false
true
5 Complete these sentences using the words below.
contracts
cool
When a metal rod is heated, it
vibrate
faster
gases
slower
expands
expands
cool
and so they move
apart
faster
. This is because the particles
and so move each other further
the metal rod is allowed to
vibrate
together
gases
slower
apart
. When
, it contracts . The particles
together
. Liquids and
expand and contract in the same way.
© Harcourt Education Ltd 2004 Catalyst 2
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Print Lesson I7 Evaporation, radiation (18 pages)
I
M
p
?
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u
^ _
UG
TY
Test yourself
Answers
Heating and cooling (continued)
6 These sentences are about changes of state when a substance is heated.
Cross out the wrong words.
a When a solid is heated, its temperature rises/falls/stays constant. At its melting
point it turns to a liquid/gas. During melting, the temperature rises/falls/stays
constant while the particles break apart/join together. When all the substance
is liquid the temperature rises/falls/stays constant.
b A liquid turns to a gas at its freezing point/melting point/boiling point.
During boiling, the temperature rises/falls/stays constant while the particles
break apart/join together. The particles are free to move about in the gas.
7 Here is a list of thermal conductors and insulators.
Underline the conductors. Circle the insulators.
wood
aluminium
polystyrene
copper
rubber
water
air
silver
brass
8 Loft insulation is made from a material that has lots of pockets of trapped air.
It works because air is a good insulator. Without loft insulation, the roof space
is full of air. Why does this not keep the heat in?
The air is free to move
so it takes the heat away by convection.
9 The diagram shows water being gently heated.
Complete the description of what happens.
When the water is heated, it expands and so becomes less
dense
. This causes the water to rise. Cooler water falls
convection
because it is more dense. So
currents are
set up in the water. In time, it will all be heated to the same
temperature
. Convection also happens in
gases
gentle
heat
.
10 How does heat reach us from the Sun, by conduction, convection
or infrared radiation?
infrared radiation
11 Which is the best explanation for when evaporation occurs?
Circle the correct letter.
A A liquid reaches its boiling point.
B The most energetic molecules escape from the liquid.
C Slow moving molecules escape from the surface of the liquid.
D A liquid gains too little energy.
© Harcourt Education Ltd 2004 Catalyst 2
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Print Lesson I7 Evaporation, radiation (18 pages)
I
M
p
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Heating and cooling
1 Some students are doing a heating experiment.
They are recording the temperature of water.
a What is the boiling point of water?
UG SS
b Copy and complete this sentence.
Energy flows from the Bunsen burner
flame to the water because ....
MS ET
2 A steel saucepan has a wooden handle.
^ _
End of unit test
Green
thermometer
1 mark
water
1 mark
heat
wood
steel
a Why would it not be sensible to use a metal handle?
1 mark
b What property of wood makes it a good choice for the handle?
1 mark
c Suggest another material that could be used to make the handle.
1 mark
3 a Copy the diagram below and draw in two arrows to show the
convection currents that are set up when the water is heated.
1 mark
water
purple crystal
heat
b Explain why the hot water moves.
c Sketch the diagram below. Add to it to show the convection
currents in air that you would expect around a bonfire.
d Air is a poor conductor of heat. Why does the air around
your house not keep the house warm?
© Harcourt Education Ltd 2004 Catalyst 2
This worksheet may have been altered from the original on the CD-ROM.
1 mark
2 marks
1 mark
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I
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p
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^ _
UG SS
MS ET
End of unit test
Green
Heating and cooling (continued)
4 Study the diagram of an iron rod
being heated.
iron rod
a What happens to the length of the
rod when it is heated and then
allowed to cool?
1 mark
b Explain what happens in terms
of the particles of iron in the rod
as the rod cools.
2 marks
5 In an experiment, the apparatus was
set up as shown in the diagram.
air
a The flask was heated gently. What
would you see in the water?
1 mark
b What would happen to the air in the
flask as it was heated to cause this?
1 mark
c What would happen to the air in the
flask as it cooled?
1 mark
d What would happen to the water in
the beaker as the flask cooled?
1 mark
6 a The diagram below shows cups of hot drinks at different
temperatures. Which one will lose heat fastest?
flask
water
1 mark
air temperature 20 °C
thermometer
40 °C
paper flag
on pin
56 °C
34 ˚C
C
B
A
b Which diagram below shows the best insulation to reduce the
heat loss from a cup?
1 mark
thermometer
water
paper
A
B
aluminium
foil
fibreglass
C
c Most good insulators are made of material that has lots of air
spaces. Why does this make them good insulators?
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End of unit test
Green
Heating and cooling (continued)
7 Rachel investigated how insulation could reduce the flow of thermal energy in
a house. She built two model houses from cardboard boxes. One was insulated with
?
loft and wall insulation, the other was not. Rachel used a sheet of plastic for the
windows and doors for both houses. Electric light bulbs were used to heat the houses.
u
A temperature sensor measured the temperature change in the houses.
^ _
insulated
walls and loft
UG SS
MS ET
temperature
sensor
+_
temperature
sensor
+_
A
B
This is the graph made by the two sensors in the model houses.
Temperature (°C)
100
80
A
60
B
40
20
0
5
10
Time (minutes)
0
15
1 mark
b Would the house with the greatest temperature rise be the
house with the insulation?
1 mark
c Why did Rachel test one house with no insulation?
1 mark
d Rachel could also have made a house with just loft insulation.
Which graph line, A, B, C or D, would show this house?
1 mark
Temperature (°C)
a Which graph line, A or B, would be the house with the greatest
temperature rise?
100
A
C
B
D
80
60
40
20
0
0
5
10
Time (minutes)
15
e Why was Rachel careful to seal all the holes in the boxes?
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MS ET
End of unit test
Red
Heating and cooling
1 Some students are doing a heating experiment. They are
recording the temperature of water.
a Give the melting and boiling points of water.
1 mark
b Copy and complete this sentence.
Energy flows from the Bunsen burner flame to
the water because ...
1 mark
2 A steel saucepan has a wooden handle.
thermometer
water
heat
wood
steel
a Why would it not be sensible to use a metal handle?
1 mark
b What property of wood makes it a good choice for the handle?
1 mark
c Suggest another material that could be used to make the handle.
1 mark
3 a Copy the diagram below and draw in two arrows to show the
convection currents that are set up when the water is heated.
1 mark
water
purple crystal
heat
b Explain why the hot water moves.
c Sketch the diagram below. Add to it to show the convection
currents in air that you would expect around a bonfire.
d Air is a poor conductor of heat. Why does the air around your
house not keep the house warm?
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2 marks
1 mark
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End of unit test
Red
Heating and cooling (continued)
4 Explain why the rod below expands when it is heated.
p
?
t
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iron rod
^ _
paper flag
on pin
UG SS
5 In an experiment, the apparatus was set up as
shown in the diagram.
air
a What would happen to the air particles in
the flask as it was heated?
1 mark
b What would happen to the air in the
flask as it cooled?
1 mark
c What would happen to the water in the
beaker as the flask cooled?
flask
water
1 mark
6 Some ice cubes were placed in a beaker of water. The beaker
was then heated with a Bunsen burner. The temperature of the
water was recorded every two minutes. The graph of the results
is shown below.
100
Temperature (°C)
MS ET
2 marks
80
60
40
20
0
0
2
4
6
8
10 12
Time (minutes)
14
16
a Explain why the temperature of the ice remains at 0 °C for
several minutes even though the ice is being heated up.
1 mark
b Explain the change from water to steam in terms of the forces
between the particles.
1 mark
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End of unit test
Red
Heating and cooling (continued)
7 What is the main method of heat transfer involved in each of
the following?
a heat travelling from the Sun to Earth
1 mark
^ _
b the air in a room heated by an electric heater
1 mark
UG SS
c heat travelling through a mat between a Bunsen burner and
the bench below
1 mark
8 Rachel investigated how insulation could reduce the flow of thermal
energy in a house. She built two model houses from cardboard
boxes. One was insulated with loft and wall insulation, the other
was not. Rachel used a sheet of plastic for the windows and doors
for both houses. Electric light bulbs were used to heat the houses.
A temperature sensor measured the temperature change in the houses.
insulated
walls and loft
+_
temperature
sensor
temperature
sensor
+_
A
B
a Why did Rachel test one house with no insulation?
1 mark
b On the graph, lines A and B are from the sensors in Rachel’s
model houses.
Rachel could also have made a house with
just loft insulation. Which graph line,
A, B, C or D, would show this house? 1 mark
c Why was Rachel careful to seal all the
holes in the boxes?
1 mark
d Rachel says that the more insulation the
less thermal energy is lost. Which results
support this conclusion?
1 mark
Temperature (°C)
MS ET
100
A
C
B
D
80
60
40
20
0
0
e Rachel says that using the temperature sensor made the results
much more reliable than if she had used a thermometer. What
was her reason for saying this?
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5
10
Time (minutes)
15
1 mark
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Heating and cooling
I
Green (NC Tier 3–6)
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End of unit test
mark scheme
?
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MS ET
Question
Answer
Mark
Level
1 a
100 °C
1
3
Energy flows from the Bunsen burner flame to the water because
the water contains less thermal energy than the flame.
1
4
A metal is a good conductor or poor insulator.
1
5
b
Good insulator or poor conductor.
1
5
c
Plastic or other strong insulating material.
1
5
1
5
1
6
2
5
The heat is taken away by convection or the warm air round the
house rises and cooler air takes its place.
1
5
The rod expands or gets longer and then contracts or gets shorter.
1
3
The particles vibrate less vigorously or more slowly
so move closer together.
1
1
6
6
Bubbles of air.
1
4
b
The air would expand.
1
4
c
The air would contract.
1
4
d
The water would go up into the flask.
1
5
6 a
B
1
4
b
C
1
4
c
Air in the material is a good insulator or poor conductor.
1
5
A
1
4
b
Yes – with insulation.
1
4
c
This was her control experiment.
1
5
d
C
1
5
e
Stop loss of thermal energy except through walls.
1
5
b
2 a
3 a
b
The hot water is less dense (than the cooler water).
c
hot air
one mark for arrows
one mark for labels
cold air
d
4 a
b
5 a
7 a
cold air
Scores in the range of:
NC Level
4–7
3
8–13
4
14–17
5
18–25
6
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6
Heating and cooling
I
Red (NC Tier 4–7)
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End of unit test
mark scheme
?
u
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Question
Answer
Mark
Level
1 a
0 °C, 100 °C
1
4
Energy flows from the Bunsen burner flame to the water because
the water contains less thermal energy than the flame.
1
4
A metal is a good conductor or poor insulator.
1
5
b
Good insulator or poor conductor.
1
5
c
Plastic or other strong insulating material.
1
5
1
5
1
6
2
5
The heat is taken away by convection or the warm air round the
house rises and cooler air takes its place.
1
5
The particles vibrate more vigorously or faster
1
6
so move further apart.
1
6
They would move faster.
1
6
b
The air would contract.
1
4
c
The water would go up into the flask.
1
5
The heat energy is going into breaking the forces between water
particles in ice.
1
7
Forces between particles in a liquid are broken.
1
7
Infrared radiation.
1
5
b
Convection
1
5
c
Conduction
1
5
This was her control experiment.
1
5
b
C
1
5
c
Stop loss of thermal energy except through walls.
1
5
d
Graph A. This is the house with the most insulation. As it has the
highest temperature rise it has lost the least thermal energy.
1
6
Would give continuous reading rather than every few minutes.
1
6
b
2 a
MS ET
3 a
b
The hot water is less dense (than the cooler water).
c
hot air
one mark for arrows
one mark for labels
cold air
d
4
5 a
6 a
b
7 a
8 a
e
cold air
Scores in the range of:
NC Level
5–10
4
11–15
5
16–18
6
19–25
7
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I
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Learning outcomes
p
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Heating and cooling
Pupil checklist
I can do
this very
well
I can do
this quite
well
I need to
do more
work on this
I can explain the difference between heat
and temperature.
I can give the melting point of ice and the
boiling point of water on the Celsius scale.
I can explain that heat energy naturally
flows from high temperature to low
temperature.
I can explain the difference between
conductors and insulators.
I can give some uses of good conductors
and insulators.
I can explain that liquids and gases are
bad thermal conductors.
I can explain why hot things expand
using the particle model.
I can draw, describe and explain a
convection current.
I can use the particle model to explain
why convection currents flow.
I can explain why evaporation causes
cooling using the particle model.
I can explain how to reduce heat loss
from a house.
I can explain changes of state using the
particle model.
I can plan and carry out an investigation
into cooling rates.
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6
Glossary
Word
Definition
absolute zero R
The energy per particle measured in degrees Celsius.
ºC
A temperature scale in which 0 ºC represents freezing water
and 100 ºC represents boiling water.
Celsius
changes of state
conduction
contract
The short way to write degrees Celsius.
A temperature scale in which 0 ºC represents freezing water
and 100 ºC represents boiling water.
convection
Energy makes things work. When anything happens, energy
is transferred.
convection current
Energy transferred from a hot object to a cooler object.
degrees Celsius
The lowest temperature possible, when all the energy has
been taken away from an object. R
dense
energy
evaporating
/evaporation
A material getting bigger.
A material getting smaller.
A dense material has a lot of particles in a small volume.
expand
The three states of matter are solid, liquid and gas.
forces of attraction R
Changing from a solid to a liquid or a liquid to a gas and
back again – melting, freezing, boiling, condensing.
infrared radiation
radiation
states of matter
temperature
thermal conductor
thermal (heat)
energy
thermal insulator
vacuum
Pulling forces between particles that hold them together. R
Thermal energy is passed from particle to particle in a solid.
A material that conducts thermal energy well.
A material that conducts thermal energy poorly.
A place where there are no particles.
The transfer of thermal energy by moving particles.
A circular movement of hot gas (or liquid) rising and cool gas
(or liquid) falling.
The change of a liquid into a gas using thermal energy
transferred from the liquid’s surroundings.
The transfer of thermal energy without particles
Carries thermal energy from a hotter to a cooler object.
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Heating and cooling
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Key words
absolute zero R
degrees Celsius
states of matter
p
?
ºC
dense
temperature
t
u
Celsius
energy
thermal conductor
^ _ changes of state
evaporating/evaporation
thermal (heat) energy
UG
conduction
expand
thermal insulator
contract
forces of attraction R
vacuum
convection
infrared radiation
convection current
radiation
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Heating and cooling
I
Sheet 1 of 1
Key words
absolute zero R
degrees Celsius
states of matter
ºC
dense
temperature
Celsius
energy
thermal conductor
changes of state
evaporating/evaporation
thermal (heat) energy
conduction
expand
thermal insulator
contract
forces of attraction R
vacuum
convection
infrared radiation
convection current
radiation
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Print Lesson I7 Evaporation, radiation (18 pages)
I
I1 What temperature?
M
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Heating and cooling
Green
1 There are 100 °C between ... freezing water and
boiling water.
Things feel hot because ... thermal energy flows
into our skin.
Water freezes and melts ... at 0 °C.
The scientific word for heat is ... thermal energy.
Things feel cold because ... thermal energy flows
out of our skin.
Water boils and condenses ... at 100 °C.
2 a, b, c
15 400 000 000 °C: centre of the Sun
100 °C: boiling point of water
79 °C: boiling point of ethanol
37 °C: temperature of the human body
4 °C: fridge temperature
0 °C: freezing point of water
−22 °C: freezer temperature
−235 °C: Triton, moon of Neptune
Red
a
i The glass would melt.
ii 59 °C
iii 42 °C
b There was less thermal (heat) energy in the hall
then there was in the living room.
1 The Celsius scale is divided into 100 divisions.
Each division marks one degree of temperature
between the freezing point and boiling point of
water.
2 We need thermometers to show us the amount
of thermal energy present.
3 There is no such thing as cold. Cold simply
means less thermal energy than somewhere else.
4 Individual answers.
I2 Temperature and energy
Green
a 80 °C
b Heating the full kettle to 100 °C.
c i The part-full kettle.
ii The full kettle.
1 a Temperature is measured in degrees Celsius
(°C).
b The energy per particle is the temperature.
c It takes more energy to increase the
temperature if there are more particles.
2 a 100 cm3. There are more particles so the total
energy is greater.
b 10 cm3 at 90 °C. The particles have more
energy at 90 °C than at 30 °C.
c 10 000 g of iron at 20 °C. There are a great
many more particles. So even though each
particle has less energy, the total energy from
all these particles is greater.
Book answers
Red
a 80 °C
b Three times as much energy.
c
i 40p
ii 200p
d i The part-full kettle.
ii The full kettle.
e
i 1 kg of lead at 400 °C.
ii 1 g of ice at −10 °C.
iii 100 g of ice at −10 °C.
1 The gate contains many more particles than the
iron poker. Although each particle in the poker
has more energy than each particle of the gate,
there are so many more particles in the gate that
its total energy is greater.
2 i 8 cm3 iron at 1000 °C.
ii Each ‘child had more money’ in the second
experiment. Each particle had more energy
at 84 °C than those at 28 °C. So the ‘total
amount of money’, the total energy in the
second experiment, was greater.
I3 Bigger and smaller
Green
a The gaps allow the tracks to expand without
bending out of shape.
b Heating makes the particles vibrate more so they
take up more space.
c Cooling makes the particles vibrate less so they
take up less space.
d i contract
ii Closer together.
1 Solids, gases and liquids all expand when they
are heated. Solids (or liquids) and liquids (or
solids) expand because the particles vibrate
more and take up more space. Gases expand
because the particles get further apart.
2 Individual answers.
3 The metal ruler contracts on a cold day so the
divisions are closer together than when the ruler
is hotter and the spaces between the divisions
are greater.
Red
a The gaps allow the concrete sections to expand
without crushing into each other in hot weather.
b Particles vibrate more in a hotter solid than in a
colder solid.
c The particles in a cooler liquid vibrate less so
they take up less space.
d When the balloon cools, the air particles inside
move more slowly and hit the insides of the
balloon with less force, so the balloon isn’t
stretched as much as before it was cooled.
1 a The rivet contracts.
b The metal plates are pulled tightly together.
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Book answers
Heating and cooling (continued)
2 a Gases have fewer particles in a certain
volume than do either a liquid or solid.
b When the temperature of a solid or liquid
increases, the particles vibrate more and take
up more space. Therefore there will be fewer
particles within a certain space, so the
density decreases.
3 The metal jam-jar lid will expand more than the
glass jar when heated. Therefore the lid will
come away from the glass more easily.
I4 All change
Green
a i An electric heater.
ii A temperature probe.
b Solid, liquid and gas.
c The temperature increases.
d Breaking the particles apart from each other.
1 To melt or boil something ... you have to put
energy in.
When you give the particles more energy ... the
temperature goes up.
When the energy is breaking the particles apart
during melting or boiling ... the temperature
doesn’t go up.
2 a To condense or freeze something you have
to remove energy from it.
b When you take energy away from the
particles the temperature decreases.
c You don’t get a drop in temperature during
freezing or condensation.
Red
a i The particles vibrate faster.
ii The energy going into the ice is used to break
the particles apart from each other.
b During boiling, the energy is used to break the
forces of attraction between the particles in the
liquid.
c
200
Steam cooling.
All of the steam
has condensed
to water.
150
Temperature
in °C
100
Water is cooled.
Steam begins
to condense to
liquid water.
50
0
0
5
10
Time in minutes
d
i Any temperature above 100 °C.
ii 100 °C
1 a The energy goes into making the particles
vibrate more.
b The energy is used to break the forces of
attraction between the particles of water.
2 a
i Label pointing to 0 °C.
ii Label pointing to 100 °C.
b i Label pointing to the part of the curve
below 0 °C.
ii Label pointing to the rising straight line
between 0 °C and 100 °C.
iii Label pointing to the flat part of the
graph at 100 °C.
iv Label pointing to the flat bit of the graph
between two and four minutes at 0 °C.
c Stars placed at both flat horizontal parts of
the graph, at the 0 °C and 100 °C sections.
3 As the water in the freezer becomes colder
energy is removed from the water, the
temperature decreases and the water
particles vibrate less. When the temperature
reaches 0 °C the energy being removed causes
new forces of attraction to be made and the
temperature remains constant. When all of the
water has become solid, the energy being
removed causes the temperature to fall to −20 °C
and the vibration of each particle becomes
less.
I5 Conduction
Green
a Individual answers.
b i The particles.
ii The energy.
iii The particles (‘children’) are held together
in fixed places by the forces of attraction.
c When all the particles reach room temperature.
d metal
e plastic
1 Conduction is when energy is passed from
particle to particle. The particles need to be
touching. The energy moves from the hotter
parts of the material to the cooler parts of the
material.
2 Aluminium, water, plastic, air, vacuum.
3 a The metal of the skewer is a very good
conductor and conducts the heat quickly
into the centre of the kebab.
b Wooden skewers would not work because
wood is a good insulator.
Red
a The surroundings contain many particles, so each
particles loses just a small amount of energy.
b Conduction stops when each particle has the
same energy and is at the same temperature.
c
i six
ii In the liquid there are different numbers of
particles touching other particles, from one
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Book answers
Heating and cooling (continued)
d
1
2
3
to six. In the gas there are only individual
particles, with no others touching them. In
the vacuum there are no particles to hit
each other so there can be no transfer of
thermal energy.
iii Solids conduct thermal energy best because
they are touching the most other particles
and can pass their energy on easily.
Gas pockets contain very few particles, which do
not touch each other, so energy is conducted
very slowly.
a aluminium, graphite, water, plastic, air
b Solids are better conductors than liquids or
gases. Metals are the best conductors, so
aluminium comes first with graphite second.
Water is a liquid so it conducts better than
gases. Plastic contains air pockets and air is a
good insulator.
c Last. There are no particles to hit each other
so there can be no transfer of thermal energy
by conduction.
a The metal of the skewer is a very good
conductor and conducts the heat quickly
into the centre of the kebab.
b Wooden skewers would not work because
wood is a good insulator.
Conduction causes thermal energy to be
transferred from hotter objects to cooler objects.
The heated end of the solid has particles with
large vibrations. As they vibrate they hit particles
next to them and energy is passed on. This
happens from each hotter particle to its cooler
neighbouring particle. This continues until each
particle has an equal amount of energy.
I6 Convection
Green
a The particles in a solid do not flow or move
around.
b two
c The purple dye moves upwards.
d All the water would be evenly coloured purple.
e The table on the right with more money.
f The particles are in fixed positions and cannot
move about.
1 Thermal energy can be transferred by
convection. Convection happens in gases (or
liquids) and liquids (or gases) but not in
solids. Convection currents happen when there
is a temperature difference. Hotter liquid or
gas rises and cooler liquid or gas falls.
2 Individual answers as: the heater on one side of
the room heats the air above it. This hotter air
begins to rise and cooler air falls to replace it
over the heater. The cool air is heated by the
heater and rises again and the process is
repeated over and over again, causing rising
convection currents of air. As the
convection currents continue, the warm air
and cooler air mix.
3 The two tables represent two different places
which hold different amounts of energy –
i.e. they have different temperatures. The
children are the particles that move to take
money (energy) from the hotter place, the table
with more money, to the other table with less
money, which is cooler. This happens in
convection. But in conduction the particles
(children) are not able to move. The particles
vibrate and knock into each other and pass
on their energy from the hotter, more
vibrating particles to the cooler, less vibrating
particles.
Red
a The particles in a solid do not flow or move
around.
b The air inside the balloon is hotter than the air
outside the balloon. Because the air inside the
balloon is hotter, it is less dense than the air
outside. Less dense materials float above more
dense materials. The hot air rises, like a cork
bobbing up through water.
c The purple dye would have been mixed with the
water after three minutes.
d There are fewer particles of the hotter liquid
than the colder liquid in the same volume.
1 As the air in the balloon cools, the particles
vibrate more slowly and there are more particles
in a certain volume than there were before. The
air becomes more dense. Materials which are
more dense than the materials around them will
sink, so the balloon falls.
2 Suitable diagram showing convection currents
of hot air rising from the land and cool sea air
coming inland to take the place of the rising hot
air.
3 The heater on one side of the room heats the air
above it. This hotter air begins to rise and cooler
air falls to replace it over the heater. The cool air
is heated by the heater and rises again and the
process is repeated over and over again, causing
rising convection currents of air. As the
convection currents continue, the warm air and
cooler air mix.
4 Two tables represent two different places that
hold different amounts of energy – i.e. they
have different temperatures. The children are
the particles which move to take money
(energy) from the hotter place, the table with
more money, to the other table with less money,
which is cooler. This happens until the money
piles on both tables are the same. This
represents a complete mixing of the fluid.
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Print Lesson I7 Evaporation, radiation (18 pages)
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Heating and cooling (continued)
I7 Evaporation, radiation
I8 Explaining the results
Green
a They break away from the liquid to become a
gas and they gain energy.
b i From our bodies.
ii From the tea in the cup.
c
i There is a vacuum around the Earth.
ii radiation
d i The children with the money.
ii The children catching the money.
iii The money being thrown.
1 Energy is transferred away from liquids by
evaporation. The particles with the most
energy leave the liquid and become part of a
gas. Radiation energy is like light. It can
travel through many materials and across a
vacuum. It transfers thermal energy from a
hotter object to a cooler object.
2 radiation – green arrows, convection – blue
arrows, evaporation – purple arrows,
conduction – red arrows
Green
a Ellen. There was a pattern.
b Increasing the mass increased the amount of
energy needed.
c Aluminium needs more energy than copper,
which needs more energy than tin.
d 720 kJ (±10 kJ)
e Sean. They would all lose energy. Such a big
difference is not likely from cooling.
f No. They still got different results.
g Yes. Keeping all the heat in still gave different
amounts of heat needed for the different metals.
1 a The particles in a warmer solid vibrate more.
b Yes. The graph shows that for a certain
amount of energy input, as Mr Smith’s 300 kJ,
only 83 g of aluminium was heated by 40 °C
whereas 346 g of tin was heated by that same
amount.
2 a copper
b aluminium
c Yes. It can be seen on the graph that for a
certain amount of each metal it takes most
energy to heat up aluminium by 40 °C, less
energy for copper and the least energy for tin.
Red
a
i
iii
iv
b i
c
1
2
3
The money.
ii The children.
The number of children.
The children passing through the turnstile.
The Earth is surrounded by a vacuum. There
can be no conduction or convection where
there are no particles to move.
ii radiation
i The middle of the room represents empty
space or a vacuum.
ii The hot object is represented by the
children with coins. The cooler object is
represented by the children receiving the
coins. The infrared radiation is represented
by the coins themselves.
Individual answers, such as: when a person
sweats, water particles leave the skin by
evaporation. When they leave they become
gas particles which are faster moving and
have more energy. This energy is taken
from the skin, so the temperature of the
skin falls.
radiation – green arrows, convection – blue
arrows, evaporation – purple arrows,
conduction – red arrows
In conduction, the children are in fixed
positions; each child passes money to the child
alongside. In convection the children move
about and pass money from one table that has
lots of money to the table with no money until
the tables have the same amounts of money. In
radiation there are two groups of children
separated by an empty space. One group with
lots of money throws money across the gap
between them to the group with no money.
Red
a Individual answers.
b The greater the mass of the block, the more
energy is needed to raise the temperature of the
block.
c The less dense the meat, the more energy is
needed to raise the temperature of a certain
mass of the metal.
d i 310 kJ (±10 kJ)
ii 720 kJ (±10 kJ)
iii 185 kJ (±10 kJ)
e
i 194 g (±10 g)
ii 83 g (±10 g)
iii 346 g (±10 g)
f 740 kJ (± 20 kJ)
g The input variables are the type of gas, the
volume of gas inside and the total mass of the
balloon. The outcome variables are the balloon’s
rise and fall.
h The greater the volume of some gases put into
the balloons, the more they will rise. For
example, the balloon with 1000 cm3 of helium
sank but the balloon with 4500 cm3 of helium
rose. The balloon with 1000 cm3 of neon sank
but the balloon with 9500 cm3 of neon rose.
For all of the other balloons that didn’t have
helium or neon in them, it didn’t matter how
much gas was put into them. They all sank.
i The greater the mass of the balloons with
certain gases inside, the more they rose. For
example, the balloon with mass 3.16 g filled
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Print Lesson I7 Evaporation, radiation (18 pages)
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Heating and cooling (continued)
with helium sank, but the balloon of mass 3.72 g
filled with helium rose, as did the one of mass
4.12 g. Similarly, the balloon of mass 3.18 g filled
with neon sank but the balloon of mass 10.68 g
filled with neon rose.
j Individual answers. Pupils choose a balloon with
either helium or neon which rose to use as their
example. They add to the balloon a mass to
make the density of the balloon, with added
mass, equal to 0.00115 g/cm3.
k 0.00083 g/cm3
l 0.00115 g/cm3
m 1.455 g
1 The balloons that contained air were more
dense than the air around them because of the
mass of the rubber in each balloon adding to the
mass of the air inside it. So the total mass of the
balloon was greater than the mass of air which
it contained.
2 a 2609 cm3
b The volume has to be greater because you
need to float the mass of the hydrogen as
well as the mass of the balloon.
c Individual answers similar to: when you heat
a certain amount of air the particles move
faster and become further apart and its
volume increases. Since the mass of the air
remains the same, the density of the air is
less than the surrounding air and the hot-air
balloon rises.
© Harcourt Education Ltd 2004 Catalyst 2
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