How can we help keep our waterways healthy?
Part 3: Temperature
How does temperature affect the health of our waterways?
Suitable for grades 3, 4, 5 and 6
Written by: Jill Reade
CONTENTS LIST
PAGE
PAGE
OVERVIEW
Introduction
and Teacher Background
Graphic Design: Lisa Eastman
2
ENGAGE
Lesson 1 - Are you hot or cold? 5
EXPLORE
Lesson 2a - Making a thermometer
Lesson 2b -What’s the temperature?
Lesson 3 - Can changing the temperature
affect the health of a water
enviroment?
EXPLAIN
Lesson 4 - How can temperature be
a problem?
7
9
10
12
PAGE
ELABORATE
Lesson 5 - Which is warmer?
- an investigation
16
EVALUATE
Lesson 6 - The Giant Freshwater 17
Lobster - a case study
www.waterwatch.org.au
1
OVERVIEW
OVERVIEW
Facts
ENGAGE
Introduction and Teacher Background Information
Lesson 1 What I Want to know
Are you hot or cold?
How
willare
I find
out experiences of hot
What
have Learnt
What
children’s
and Icold?
What do they know about how temperature affects
living things?
Lesson 2
a - Making a thermometer
b - What’s the temperature?
Practise the skill of reading a scale and build
understanding of how a thermometer works.
Lesson 3
Can changing the temperature affect
the health of a water environment?
Use the “Hay infusion” experiment to investigate some
ways in which temperature can affect the health of
a water environment.
Lesson 4
How can temperature be a problem?
Examine the ways in which temperature may be changed
in an aquatic environment. This section includes an
optional teacher demonstrated activity to show that
increasing temperature releases oxygen from water.
EXPLORE
EXPLAIN
ELABORATE
EVALUATE
Lesson 5
Which is warmer?
- an investigation
Plan an experiment to investigate the connection
between shade and temperature.
Lesson 6
The Giant Freshwater Lobster – a case study
Use the knowledge acquired to examine the problem
of temperature change in a real life context.
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
2
OVERVIEW
INTRODUCTION
This series of learning activities is part of
a wider learning sequence based around
the guiding question - How can we help keep
our waterways healthy?
The entire unit consists of five parts
– an introduction to water, then sections
on turbidity, temperature, salinity and
a final section on water life and habitat.
The sequence uses the 5Es model for
teaching and learning in Science.
SCIENCE OUTCOMES
Students will be able to:
• Explain their understanding of hot and cold
in the context of water.
• Explain how a simple thermometer works
and read a temperature scale.
• Understand how temperature is measured
and in what units.
• Identify ways that temperature can affect
a waterway.
• Explain how changes in a waterway’s
temperature can occur.
• Follow directions to conduct simple
investigations.
• Design a simple fair test to investigate
how temperature can effect a change in
the health of a waterway.
• Make measurements and observations.
How does temperature affect
Teacher Background Information
the health of a waterway?
What is temperature?
Temperature is the property of a system
which helps to measure how hot or cold
things are. Something that is hot has a
higher temperature than something that
is cool. The temperature of an item has to
do with the amount of energy it has in its
particles. Hot and cold, are relative terms.
On a cold day an item at room temperature
can feel relatively warm whereas on a
very hot day the same item will feel cool.
While hot and cold are relative ideas,
temperature is measured on a fixed
scale. We measure temperature using
a thermometer. Thermometers contain a
The role of temperature in nature
Temperature plays an important role in
lots of areas in the natural world. Many
physical properties of materials depend
on temperature, e.g. whether the material
is commonly a solid, liquid or gas, and its
density, solubility and conductivity
(salinity) all depend on the temperature.
Temperature is an important element of
the weather since it controls or influences
the other elements, e.g. humidity,
clouds, air pressure and precipitation as
well as the wind.
Temperature plays a major role in
determining the rate and extent to which
liquid which expands at a slow rate as
the temperature rises, so that a scale can
be created which will give a consistent
reading for a particular amount of warmth
in the surrounding substance.
There are a number of temperature
scales used in the world today. In Australia,
and in most other places in the world,
we use the Celsius temperature scale
(symbol: °C) which was initially based on
the boiling point of water and the melting
point of ice. The melting point of ice was
given the scale reading of zero degrees
whereas the boiling point of water was
read as one hundred degrees.
chemical reactions such as respiration,
digestion and photosynthesis occur in
living things. This is one reason why the
human body has some complex ways for
maintaining its normal temperature at 37 °C,
since temperatures only a few degrees
higher can result in harmful reactions with
serious consequences. (Most people are
aware that when they are ‘running a
temperature’ they feel unwell and an
important reason for taking medication
is to bring the body temperature down
to normal.)
Continues on next page!
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
3
OVERVIEW
Temperature - Continuing from previous page.
CONNECTIONS TO
THE STATEMENT OF LEARNING
Year 3 Science as a Human Endeavour
• Students share responsibility for the quality
of their immediate environments.
Year 3 Science as a Way to Know
• Students begin asking questions
and make predictions.
• Students plan and conduct simple
investigations. They collect, record
and present data.
• Students share findings, discuss how
an investigation could be changed
and consider fairness of tests.
Year 5 Science as a Human Endeavour
• Students consider appropriate ethical issues
and consequences of human activity. They
investigate how their actions contribute
to sustainability of local environments.
Year 5 Science as a Way to Know
• Students derive questions and predictions
for testing. They plan an investigation,
collect data, checking and repeating
observations.
• Students present data in appropriate ways
and then identify patterns. They compare
results with predictions and draw
conclusions.
In waterways temperature changes can
drastically affect the living creatures present in
the area and, as most of these animals have
limited ability to control their own temperature
as they are cold blooded, the effects can be
disastrous.
Temperature rises in water can also affect the
amount of oxygen present, as warmer water
contains less oxygen. To help think about this,
consider a pan heating on a stove top – as it
heats up bubbles of gas start to rise to the
surface. This is the dissolved oxygen in the
water being released. As the water nears
boiling point some of the bubbles contain
steam as well.
Finally, as temperature rises, the growth of
bacteria which are feeding on plant material
increases, and the rotting vegetation can foul
the water and use up the oxygen which is in
the water.
100ºC - Boiling point of water at sea level.
60ºC - 70ºC - Cooking temperature range.
Note These statements have been summarised.
37ºC - Human body temperature.
Curriculum Connections to other learning areas
Numeracy – measurement, reading scales,
using informal and formal measurement.
Literacy –students maintain a journal of their
activities, thoughts and ideas as they proceed
through the unit. Teachers use a word wall.
20ºC - Danger temperature for many water animals.
What changes the temperature of a waterway?
Changes in water temperature can be affected
by some or all of the following factors:
• Air temperature
– as the day warms up the water warms
• Ground water entering the waterway
– this is often colder than surface water
• Stormwater runoff
– this can be warm if the day is warm or
the water has been running over warm
black surfaces
• Turbidity
– the extra colour absorbs heat more
effectively
• The amount of shade around the waterway
– shade protects the water from the sun
• Warmer or colder water running into
a waterway
– sometimes factories or powers stations
release water
Surface temperatures are also usually warmer
than the bottom of a stream. Smaller streams
are usually more consistent in temperature than
larger ones owing to even mixing of the water.
Water temperature varies over the day with
smaller streams being more affected than
larger water bodies.
Further information on the effect of temperature on waterways
can be found in the Tasmanian Waterwatch Reference Manual.
5ºC - 15ºC - Range of water temperatures in Tasmanian streams.
0ºC - Freezing point of water.
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
4
ENGAGE
Lesson 1
OVERVIEW
What do the words hot and cold mean?
What does temperature tell us? How does
temperature affect water creatures?
Are you hot or cold?
Lesson steps
1.
Students:
• Share experiences of hot and cold.
• Record ways that warmth and cold
can affect them and other living things.
• Compare the sensation of warm and cold.
As an introduction have a fan to fan your face
or a warm coat and gloves. Make a comment
about how warm/cold it is. Place the headings
HOT and COLD on the board or on butcher’s
paper. Tell the class they are going to explore
the effects of hot and cold on water creatures.
z
z
z
HELPFUL HINTS
• A lesson focus is to help children understand
that living things are affected by how hot or
cold they are.
• Related ideas are hibernation and the meaning
of cold and warm-blooded.
• Many Australian animals hibernate, including
echidnas, ladybirds, long-necked turtles,
mountain pygmy-possums and wombats.
• Warm-blooded animals are like humans,
other mammals and birds which maintain
their own internal body temperature.
• Cold-blooded animals such as fish, reptiles
and invertebrates (animals without backbones)
have a body temperature near that of their
surrounding environment.
• Discuss things the students do that make
them feel warm or cool such as moving into
the shade on a warm day. Sharing these
experiences will help them to understand
later some ways in which water temperature
may be varied depending on what is
happening in the environment.
2.
Ask students to close their eyes and picture
a time when they have felt very hot. Ask them
to think of words to describe how they felt
(apart from hot). Ask them to give a thumbs-up
signal when they have a word in their mind.
3.
Ask them to quietly share with their neighbour
their experience or words.
4.
Now have them share their words or experience
with the whole class. Record responses on the board.
5.
Repeat the same questions, thinking of a time
when they felt cold. Record their responses
on the board.
6.
Sort their experiences into different categories
depending on what caused them to feel hot
or cold – hot experiences may include; it was
a hot day, being unwell, having a hot drink
or food, being in a sauna or hot bath.
7.
Ask them - How does being hot or cold
change what you do? List their ideas on
the board. (They may suggest it changes
their activities or what they wear, what
they eat, or even how they feel.)
z
z
z
z
z zz
z
Echidnas hibernate in burrows under ground
during the winter season.
8.
Question - Do you think that being
hot or cold affects other living things?
Note If no ideas arise read a book such as
"The Magic School Bus Gets Cold Feet: a
book about hot and cold-blooded animals",
by Tracey West, to help gain some ideas.
9.
Introduce the student worksheet
“Are you hot or cold?”. Discuss
the questions from the sheet.
Distribute copies and record ideas
using drawing and/or writing.
10.
Use the sheets to create a class summary
in answer to each question.
11.
Record any questions as they arise.
Click h
er
this wo e to see
rkshee
t!
Continues on next page!
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
5
ENGAGE
Lesson 1 - Continuing from previous page
Do hot and cold always feel the same?
EQUIPMENT
• 4 bowls of water
• paper to soak up the spillage
Optional activity/demonstration
Prepare four bowls. Fill the first with ice water, the second and third with
room temperature water, and the fourth with hot water (but not hot enough
to burn a hand).
TEACHER’S NOTE
The hand which was in the cold water
should now feel warm and the hand that
was in the hot water should now feel cool.
Heat flows out of the warm hand into the
room temperature water. The loss of heat
from the warm hand makes it feel cold.
Heat flows from the room temperature
water into the cold hand. This gain in heat
makes the cold hand feel warm.
1.
3.
2.
4.
REFERENCES
www.educationworld.com/a_lesson/lesson/lesson328b.shtml
www.learnnc.org/glossary/word+wall
www.k5geosource.org/activities/lit/pg4.html
es each
1. How do
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Suggestion
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Word W
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Place one hand in hot water and one hand in cold water for about 15 seconds.
Now put each hand in one of the bowls containing room temperature water.
cold-blooded
temperature
thermometer
pollution
warm-blooded
hibernation
Celsius
thermal
Add to the word wall as you go through the lessons.
energy
invertebrate
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
6
EXPLORE
Lesson 2a
Making a thermometer
OVERVIEW
To provide hands on experience of how a
thermometer works.
Students
• Construct a simple thermometer
• Record observations and measurements
• Think about scale
Note For more teacher background
information on this activity see the extra
material on the next page.
EQUIPMENT FOR EACH GROUP
• a glass jar or bottle with a water-tight
lid - the lid should be the screw-on type
• 1 drill or a hammer and a large nail
• blu-tack or chewing gum
• thin clear drinking straws - about 23 cm
• food colouring (optional but helpful)
• a commercial thermometer
HELPFUL HINTS
• Collect glass jars with lids ahead of time.
• Have someone help with drilling the lids
or do this step ahead of time.
To complete this activity on temperature
and reading a thermometer use the extension
activity outlined in Lesson 2 b where students
measure air and water temperatures around
the school.
Lesson steps
1.
To start, record where and how people
use thermometers and what they look like.
2.
Now drill or punch a hole in the lid of a jar.
The hole should be as near to the diameter
of the straw as you can get.
3.
Put the end of a straw into the hole, and
then seal around the hole with blu-tack
both on the inside and the outside of the lid.
It should look something like the picture.
4.
Fill the jar to the brim with cold (icy) water.
Add food colouring if you wish and stir it up.
5.
Put the jar on a table or sink to keep it steady.
Make sure the jar is really full to keep out all
the air. (Water will overflow when the lid goes
on the jar.)
6.
Put the lid on the jar. (Some water may be
in the straw. )
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?
?
? ? ? ??
some thin
nkin
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1. What
makess the water
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go up
p the straw?
2. How could yo
u make it
go down the stra
w?
3. What does te
mperature tell us
?
7.
Place the jar in a bowl and fill it half full of
warm water. (You could also place the jar
in the sun).
8.
Watch the level of the liquid in the straw
to see what happens.
9.
Make a record in your science journal
of what you see, and draw a diagram
to show what happened.
Don’t forget
to clean up!
energy
invertebrate
Continues on next page!
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
7
EXPLORE
Lesson 2a - Continuing from previous page
THE BULB THERMOMETER
This simple bulb thermometer works pretty
well. But it also has a few problems:
• The working fluid is water, it cannot
measure temperatures below zero
degrees C (the water would freeze)
or above 100 degrees C (the water
would boil).
• The "bulb" (the jar) is so large, it takes
a long time for the thermometer to
reach the same temperature as the object
it is measuring.
• The top of the straw is open, so the water
may evaporate or pick up dust.
• Sealing mercury in a small glass
thermometer solved some problems.
Mercury, however is toxic so modern
school thermometers often use an
alcohol solution.
Extra Background Information
About the thermometer
you have made
The way in which this thermometer works is
reasonably simple. When the thermometer is
placed in warm water or a warm place, the water
expands up the straw. This type of expansion
happens every day to water or other liquids as
they warm up, but we don't really notice it because
the amount of expansion is fairly small. Here, because
the expanding water is forced into a narrow straw,
it is much more obvious. We can see it.
The Galileo thermometer consists of a sealed glass tube
that is filled with water and several floating bubbles.
The bubbles are glass spheres filled with a coloured liquid
mixture. This liquid mixture may contain alcohol, or it might
simply be water with food colouring.
To check how a Galileo thermometer works follow this link:
www.howstuffworks.com/question663.htm
energy
The Galileo Thermometer
invertebrate
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
8
EXPLORE
Lesson 2b
OVERVIEW
Students make scientific measurements and
collect and interpret temperature data.
Students
• Measure air and water temperature.
• Record and manipulate data.
• Draw conclusions.
What’s the temperature?
Lesson steps
1.
Begin by measuring the temperature
of the air in the classroom. Make sure
you know how to read the thermometer.
2.
Make 10 temperature measurements
around the school grounds, carefully
recording the location of each
measurement. Each measurement
should be written in a table.
EQUIPMENT
• a thermometer for each pair of students
3.
HELPFUL HINTS
• This activity could be completed along
a waterway.
• To measure water temperatures from a creek
use a plastic container to collect samples.
• The common site temperature measurement
checks for variations in temperature over a
period of time. If there is variation calculate
an average.
• Some simple school thermometers have scale
charts that are not attached firmly to the tube.
Check for this before starting to measure.
SAFETY NOTE
Handle thermometers carefully.
4.
5.
One measurement for all groups
must be at a pre-chosen, shady site,
one metre above the ground.
(The weather bureau measures
temperature in this way.)
80
70
60
50
38ºC
30
At one of the other locations, measure
the temperature of the air a few centimetres
above the ground, one metre above
the ground and at least two metres
above the ground (higher if possible).
Back in the classroom, decide which
one or more of your measurements
best shows the outside air temperature,
and explain your selection. All temperature
measurements at the common site
should be collected and shared on
the board.
!
Now continue your
Suggestion
investigation of temperature by measuring
water temperatures around the school or in
a near-by stream. (Set up plastic containers
of water in the classroom and in sunny and
shady areas.)
Measure temperature changes over the day
to see how it varies.
Reference: Air Watch booklet activities
40
20
10
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Temperature
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hinking questio
ns
1. Why arre
1
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e di
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ween temp
peratures
measu
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om
mmon site?
2. How coul
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easure
em
ments from
the common site
to work out wha
t the actual
temperature was
energy
there?
3. What patterns
did you notice in
the temperature
invertebrate
s?
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
9
EXPLORE
ACTIV
IT
Students
• Set up three mini aquatic environments.
• Place one in a cool place and one in a
warm place and one at room temperature.
• Record and discuss their observations.
• Decide which environment is better for
aquatic animals.
1.
2.
Collect three jars and add a tablespoon
of hay/dry grass to each one. Try to make
the amount of hay the same in each jar.
The hay provides food for little animals
in the water to live on over the time
of the investigation.
EQUIPMENT FOR EACH GROUP
• 2 glass or strong plastic jars with lids
• pond, river or rain water, not tap water
• a handful of hay or old dry grass
• access to a fridge and a sunny window
or other fairly warm environment
3.
Add river, lake or rain water (not tap water)
to each jar or cup so that the cup is about
three quarters full and the hay is covered.
4.
Cover all jars so that the light cannot affect them.
Note This activity takes about a week
to complete.
5.
Place one jar in a fridge at 4ºC, leave one jar
at room temperature and store the final one
in a warm place – an incubator is ideal or in
a sunny window or under a heat lamp. Record
what the hay and water look like and smell
like to begin with.
Remember! - the jar in the warm place may
get cold at night so place it in the warmest
place you can find each night.
Note Hay (or grass) is a handy material to use
to represent a wide variety of plant material.
Ask students to suggest ways plant material may
get into rivers and streams.
ULT T
IME
k
Can changing the temperature affect
Lesson steps
the health of a waterway enviroment?
OVERVIEW
What happens to a mini aquatic environment
when the temperature is warmer?
HELPFUL HINTS
• The bacteria and other organisms were in
the pond water, on the grass or in the air.
They could not be seen to start with as there
were not enough of them. They have not
appeared out of nowhere.
• Treated tap water will not work for this
experiment as the chlorine in treated water
kills bacteria in the air or on the grass.
Y RES
1 wee
Lesson 3
6.
Does increasing temperature change
what happens to living organisms in
a water environment?
2.
3.
After the first two days check the look
and the smell of the water and hay.
Then each day after this, check if the water
needs topping up. Look for any changes
in the appearance or smell. If you use
a glass jar take photographs to show
any changes.
Continues on next page!
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
10
EXPLORE
Lesson 3 - Continuing from previous page
SAFETY NOTE
Children who have handled the hay infusion
should make sure they wash their hands
thoroughly with soap and water.
7.
Draw up a record sheet, like this one,
in your science journal.
What’s happening in our jars?
Day/date
In the fridge
Looks like
Smells like
In the classroom
Looks like
Smells like
In a sunny window
Looks like
Smells like
Day 1
Day 2
Day 3
Don’t forget
to clean up!
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HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
11
EXPLORE
Lesson 4
OVERVIEW
How can temperature affect aquatic life
and how does temperature change in
a waterway? Here is the science.
Students
• Discuss ideas about temperature and
the water environment.
• Research and record ways in which
natural and human activity can affect
water temperature.
• Explain some ways in which temperature
variation can affect an animal’s environment.
• Suggest ways the community can work
to overcome the problems.
How can temperature be a problem?
Lesson steps
1.
Look back over ideas about hot and cold.
Examine the photographs and records from
your investigation into the effect of temperature
on water environments.
2.
Think
• How do changes in temperature affect a water
animal’s environment?
• Can human activity change the temperature
of a waterway?
Click h
er
printa e for
ble ver
sion!
Here is some information to help you think about the first question.
How does a temperature change affect water life?
An increase in temperature can have a big effect on life in a waterway.
Temperature changes affect these aspects of the water environment:
• The oxygen content of water. Warmer water holds
less oxygen than cooler water. This means that
there is less oxygen for the animals to breathe.
• Photosynthesis (food production) by water plants the warmer the water the more food is produced.
• Animals digest food faster when it is warmer.
• Bacteria breakdown rubbish faster when it is warmer.
• Animals are more sensitive to toxic wastes, parasites,
and diseases in warm water.
All water animals have a temperature range that is
best for their health. Fish and most water (aquatic)
animals are affected by temperature and they can
sense very small temperature changes.
Fish, reptiles and frogs are cold-blooded. This
means the way their body works and grows
changes as the temperature does.
Some fish process food best in colder water, while
others prefer warmer water. Each species of fish has
a best temperature range for growth and at temperatures
above, or below, this range their growth rate slows down.
Spawning (mating and laying eggs) success
also depends on temperature. Each species
has its own best temperature range for
spawning.
The survival of newly hatched baby animals
is dependent on the temperature staying
within a certain range. If temperatures are
too high for a long time, the baby animals
will die. Very cold conditions can be as
bad for spawning as warm conditions
because some fish cannot spawn below
a certain temperature.
Many macro-invertebrates that live on
the bottom of a waterway are also
sensitive to water temperature.
I like my
water to be
just right!
Continues on next page!
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
12
EXPLAIN
Lesson 4 - Continuing from previous page
How can temperature be a problem?
Lesson steps
3. Now move on to the factors that influence the temperature
of waterways.
Read the short introduction below then research
the ways in which human activity can change temperature
in a stream. Using the table format shown below, fill in
the information about the change and what causes it.
What humans do can cause thermal or heat pollution in a
waterway. Here is a list of activities which raise the temperatures
of streams and rivers. The effects are worst in the summer, because
water flow is lower so the higher temperatures create more
stress on water life.
4. Use your science journal to record the table of natural
events and human activities which may influence water
temperature in a catchment and try to explain how
the change happens.
How will the temperature
change?
Time of day
Time of year
Human activities which lead to higher temperatures include:
Amount of water
• Cutting down of trees and other bank vegetation which
allows more sunlight to reach and heat the water. Fewer trees
can also mean more erosion, which adds more soil particles
to the water and these particles absorb heat from the sun.
Water flow - quick/slow
• Building dams on a waterway which cause the river to slow
down and absorb more heat from the sun. If the pool behind
the dam is larger than the original river channel, more of
the water surface is open to sunlight.
Is the change natural
or caused by people?
Trees on the riverbank
Discharge from factories
or power plants
Stormwater runoff
Turbidity
• Release of warmed water from industry and power plants.
• Release of urban stormwater that has been warmed by
running over hot paved surfaces (streets, parking areas)
before it runs into the stream.
For more information visit:
www.cleanwatercampaign.com/html/597.htm
www.waterencyclopedia.com/Re-St/Runoff-Factors-Affecting.html
5. Activity
Now produce a PowerPoint presentation,
or a poster to show your understanding.
Continues on next page!
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
13
EXPLAIN
Lesson 4 - Continuing from previous page
Extra information for teachers
Warm and cold blooded
A cold-blooded animal has no way to control
its body temperature and keep it constant as
we do. A cold-blooded animal, like a fish,
depends on its surroundings to regulate
(control) its body temperature. A fish living
in warm, tropical waters has a higher body
temperature than a fish living in the Antarctic.
A lizard sunning itself on a rock is trying
to increase its body temperature to in turn
increase its metabolic rate (the rate at which
its body works). A desert tortoise hibernates
during the winter months because of colder
conditions which slow its metabolic
functions.
Reference:
http//coolcosmos.ipac.caltech.edu/image_galleries/ir_zoo/coldwarm.html
Frogs belong to the group of animals
called Amphibians. They are an example
of so called cold blooded animals.
Continues on next page!
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
14
EXPLAIN
Lesson 4 - Continuing from previous page
EXTENSION
Read the material on the following link to find
out about cold water pollution.
www.dnr.nsw.gov.au/water/cold_water.shtml
Write a short report in a science journal
giving information about cold water pollution
explaining what it is and why it is a problem.
Optional activity - a teacher demonstration
Lesson steps
Part 1
To show that water contains gas, open a fresh
bottle of carbonated water. Students will see
gas bubbles form in the water the instant you
release the pressure. If you place a plastic bag
over the top of the bottle it slowly fills with gas.
This gas is carbon dioxide. The high pressure
inside the bottle causes more carbon dioxide to
dissolve in the water. Ask the children if they
think that tap water contains dissolved gas. Show
them a glass that you had filled with tap water
the previous day. They will see that the inside
of the glass is lined with bubbles. Ask students
to explain where these bubbles came from.
Part 2
Now use the following demonstration to show
how temperature affects the amount of gas that
can dissolve in water. Fill one bowl three-quarters
full with hot tap water and another bowl
three-quarters full with cold tap water. Fill two
plastic cups halfway with any type of carbonated
soda or sparkling water. Set a cup into each of
the bowls and observe. Ask students to compare
how the water in the two cups behaves.
(In the hot water, the bubbles will be bigger and rise
to the surface more quickly than in the cold water.)
(The bubbles form as gas comes out of solution. Tap
water is pressurized to help it flow through the water
pipes. Pressure influences the amount of gas dissolved
in water. In the open glass, there is less pressure than
in the water pipes, and some of the dissolved gases
come out of solution, forming bubbles.)
?
?
?
?
????
what do you thin
k?
1. In which cup
will the soda go
flat first?
(They both go flat,
but the soda in
the hot-water bath
will go flat sooner
than the soda in th
e cold-water bath.)
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
15
ELABORATE
Lesson 5
Which is warmer?
- an investigation
OVERVIEW
Students design an experiment to investigate
the effect of shade on water temperature.
Students
• Use information from previous learning
to generate ideas.
• Design an experiment to test the effect
of shade on water temperature.
• Make observations and collect data.
• Draw conclusions based on their evidence.
• Suggest ways in which people can help
solve the problem.
POSSIBLE EQUIPMENT
• Thermometers
• Containers
• Shade cloth or similar material
• A source of heat – such as a sunny window
Lesson steps
1.
The question for investigation is –
Which water will be warmer on a hot day
– a waterway surrounded by shady trees
or water with no shady trees around it?
2.
Use the CREST investigation planner
to help organise your thinking. Click h
er
this wo e to see
rkshee
t!
3.
4.
What materials could you use for your
investigation? Have a look at the materials
that your teacher has provided as they may
give you some ideas.
5.
Now state what you want to do in your
investigation - I will change the ..............
and, I will measure the ..............
6.
Work in groups to plan out the investigation.
Have your teacher check your plan before you
get started.
7.
When you have finished with your investigation
and you are happy with your results, you should
write a report.
!
Suggestion
This investigation into
the effect of shade on the temperature of
a waterway could be replaced by an
investigation into the effect of turbidity
on water temperature.
First list the factors which may influence
your investigation such as the amount
of shade. Then decide what you will measure.
8.
Your group has probably produced some data
that can be recorded on a graph. The graph can
be included as part of your report on the investigation.
Shady waterway
Photographer: Lisa Eastman
9.
What do you think?
• What happens to the water temperature
when you have more shade over the water?
• How will this affect water animals that like
cool water?
• Why might people cut down trees around
waterways?
• How could the community help overcome
the problem?
10. To finish your report explain any problems
that you had when your group carried out
the investigation and any changes that you
would make to help make the investigation
a fair test.
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
16
EVALUATE
Lesson 6
OVERVIEW
Reflect on the effects of temperature on
waterways in a local situation.
Click h
er
printa e for
ble ver
sion!
The Giant Freshwater Lobster - a case study
Students
• Review the lesson by looking over
information they have collected.
• Comment on possible reasons for the decline
in lobster numbers.
• Relate the lobster’s problems with
temperature to changes in the environment.
• Reflect on their learning and how it
might help them to better care for
their environment.
Introduction
The giant lobster is one of Tasmania’s important
endangered species. The Tasmanian Giant Freshwater
Lobster (Astacopsis gouldi) is the largest freshwater
invertebrate in the world. Originally the lobster was
found in waterways all the way from the Arthur River
in the north-west, and across the north of the state
including all rivers flowing into the Bass Strait (except
the Tamar catchment). Today the lobster has vanished
or its numbers are dropping within many of these rivers
and so it is only found in a few places.
Lesson steps
What is the lobster like?
The freshwater lobster is large. Some specimens of
the lobster reach more than 5 kilograms in weight
and over 80 cm in length. Even though some lobsters
which have grown to such a large size are known,
the main cause of its threatened status is the fact
that it grows very slowly, at a pace of around 5-10 mm
per year. It reaches adult age at 9 years in males and
14 years in females. (That is pretty old for an invertebrate.)
Females reproduce only every two years, so the lobster
is very vulnerable to any change in its environment
or over-fishing by humans.
1. Make a summary of the information you have
learnt about the temperature of waterways and
what people do.
• How can what humans do change
the temperature of waterways?
• How does temperature change affect
living things?
2. Now have a look at a real life case study.
Where do we find lobsters?
Lobsters are found in flowing and still waters. Adults
like to live in still, deep pools, sheltered beneath
submerged logs and overhanging banks. They like
well-shaded, clean streams and cooler conditions.
Scientists have been finding out information about
the lobster for a long time. Some scientists did a study
at the Aquaculture Centre in Launceston about 20 years
ago, to find out if the lobster could be farmed commercially.
One of the things the scientists found out was that if
the water temperature was kept above 20ºC for 3 weeks
then lobsters would die. In fact if lobsters were kept in
water at 20ºC they would often climb out of their tanks.
The problem facing lobsters now is that in some areas
in summer, some waterways containing lobsters have
water at 20ºC. The main streams where this happens are
ones with fewer trees and shrubs around them. (This is
mainly due to clearing of the tall trees and shrubs which
can raise the temperature by up to 6ºC.) Many waterways
with large trees around them stay at a comfortable 18ºC
in summer, with some of the smaller streams staying
around 16ºC even on the hottest days.
Continues on next page!
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
17
EVALUATE
Lesson 6 - Continuing from previous page
tth
hinking questio
ns
The Giant Freshwater Lobster - a case study
Rising temperatures cause the lobsters to seek cooler
waters. Over a year or so, this would leave areas which
regularly heat up to 20ºC with no lobsters. This is especially
a concern in smaller waterways. The bigger river systems
such as the Arthur River would be okay because they have
enough depth to cool the water on the bottom.
Creeks, such as Big Creek at Wynyard, parts of
the Rubicon River and Don River would have few
lobsters living in them.
C arif
Cl
ify any new wor
o ds and ad
dd
d th
t em
m to yo
ou
urr worrd
1. What is ha
d wall.
h ppening to th
e numbers
r
of
the freshw
h ater lobster?
2. How are tem
perature change
s contributing
to the problem?
3. Where is the
problem the wor
st and why?
4. How are hum
an activities cont
ributing to
this problem?
5. How can the
community help
look after
the lobster?
Todd Walsh, “the lobster man” says “I have never
captured a lobster in Big Creek at Wynyard although
I regularly capture juveniles in other creeks when I
do macro-invertebrate sampling”.
While there are no recorded incidents of mass deaths,
one reason for this is that many of the lobsters would
die unseen under the water.
To finish
Prepare a presentation to the class or a
community group on the problems faced
by the freshwater lobster and how
the situation could be assisted.
To complete your work write a reflection in your journal:
• What new things did you learn during this unit?
• What activity did you enjoy the most? Why?
• What was an activity you would like to change or add to?
Why?
• What did you learn about human impact on
the environment and how the community could help
look after waterways?
Giant freshwater lobster (A. gouldi)
habitat in Tasmania.
References
Modified information from Todd Walsh and from the following sites:
www.tased.edu.au/tasonline/dorsetww/Lobsterpage.html
www.environment.gov.au/biodiversity/threatened/publications/lobster.html
HOW CAN WE HELP KEEP OUR WATERWAYS HEALTHY? Part 3: Temperature
18
FOR STUDENTS
ENGAGE
Are you hot or cold?
Write your ideas here.
Name ________________________________ Date ________________
What does hot feel like?
How do I measure
how hot or cold
things are?
What does cold feel like?
How can I help
make myself hot?
How could being
hot or cold affect
other living things?
How can I help
make myself cool?
Return to: PART 3, Lesson 1 – Are you hot or cold?
FOR STUDENTS
EXPLAIN
How does a temperature change
affect water life?
An increase in temperature can have
a big effect on life in a waterway.
Temperature changes affect these
aspects of the water environment:
• The oxygen content of water.
Warmer water holds less oxygen
than cooler water. This means
that there is less oxygen for
the animals to breathe.
• Photosynthesis (food production)
by water plants; the warmer the water
the more food is produced.
• Animals digest food faster when
it is warmer.
• Bacteria breakdown rubbish faster
when it is warmer.
• Animals are more sensitive to
toxic wastes, parasites and diseases
in warm water.
All water animals have a temperature
range that is best for their health. Fish
and most water (aquatic) animals are
affected by temperature and they can
sense very small temperature changes.
Fish, reptiles and frogs are cold-blooded.
This means the way their body works
and grows changes as the temperature
does.
Some fish process food best in colder
water, while others prefer warmer
water. Each species of fish has a best
temperature range for growth and
at temperatures above, or below, this
range their growth rate slows down.
Spawning (mating and laying eggs)
success also depends on temperature.
Each species has its own best
temperature range for spawning.
The survival of newly hatched
baby animals is dependent on
the temperature staying within a
certain range. If temperatures are too
high for a long time, the baby animals
will die. Very cold temperatures can
be as bad for spawning as warm
temperatures because some fish
cannot spawn below a certain
temperature.
Many macro-invertebrates that live
on the bottom of a waterway are also
sensitive to water temperature.
Continues on next page!
Return to: PART 3, Lesson 4 – How can temperature be a problem?
page 1/2
FOR STUDENTS
EXPLAIN - How does a temperature change affect water life?
Continuing from previous page.
How does human activity change
the temperature in a waterway?
What humans do can cause thermal
or heat pollution in a waterway.
• Release of warmed water from
industry and power plants.
Here is a list of activities which raise
the temperatures of streams and rivers.
The effects are worst in the summer,
because water flow is lower so the
higher temperatures create more stress
on water life.
• Urban stormwater that has taken in
heat from paved surfaces (streets,
parking areas) before it runs into
the stream.
Human activities which lead to
higher water temperatures include:
INDUSTRY
• Erosion, which adds more particles
in suspension in the water; these
particles absorb heat from the sun.
• Cutting down of trees and other bank
vegetation which allows more
sunlight to reach and heat the water.
• Building dams on a waterway
which cause the river to slow down
and take in more heat from the sun.
If the pool behind the dam is larger
than the original river channel, more
of the water surface is open to
sunlight.
Return to: PART 3, Lesson 4 – How can temperature be a problem?
page 2/2
FOR STUDENTS
ELABORATE
Temperature investigation student planning sheet
CREST Investigation Planner
My Investigation is:
Brainstorm
- all the things
that could affect
this investigation
Choosing Variables
I will change
I will measure
Things I will
keep the same
Return to: PART 3, Lesson 5 - Which is warmer? - an investigation
FOR STUDENTS
EVALUATE
A case study The Giant Freshwater Lobster
Introduction
The giant lobster is one of Tasmania’s
important endangered species.
The Tasmanian Giant Freshwater
Lobster (Astacopsis gouldi) is the
largest freshwater invertebrate in
the world.
Originally the lobster was found in
waterways all the way from the Arthur
River in the north-west, and across
the north of the state including all
rivers flowing into the Bass Strait
(except the Tamar catchment).
Today the lobster has vanished or
its numbers are dropping within many
of these rivers and so it is only found in
a few places.
What is the lobster like?
The freshwater lobster is large. Some
specimens of the lobster reach more
than 5 kilograms in weight and over
80 cm in length.
Even though some lobsters which have
grown to such a large size are known,
the main cause of its threatened status
is the fact that it grows very slowly, at a
pace of around 5-10 mm per year.
It reaches adult age at 9 years, in males,
and 14 years, in females. (That is pretty
old for an invertebrate).
Females reproduce only every two
years, so the lobster is very vulnerable
to any change in its environment or
over-fishing by humans.
Where do we find lobsters?
Lobsters are found in flowing and still
waters. Adults like to live in still, deep
pools, sheltered beneath submerged
logs and overhanging banks. They like
well-shaded, clean streams and cooler
conditions.
Giant freshwater lobster (A. gouldi)
habitat in Tasmania.
Continues on next page!
Return to: PART 3, Lesson 6 - The Giant Freshwater Lobster - a case study
page 1/2
FOR STUDENTS
EVALUATE- A case study - The Giant Freshwater Lobster
Continuing from previous page.
Scientists have been finding out
information about the lobster for a
long time. Some scientists did a study at
the Aquaculture centre in Launceston
about 20 years ago, to find out if the
lobster could be farmed commercially.
One of the things the scientists found
out was that if the water temperature
was kept above 20°C for 3 weeks then
lobsters would die. In fact if lobsters
were kept in water at 20°C they would
often climb out of their tanks.
The problem facing lobsters now is
that in some areas in summer, some
waterways containing lobsters have
water at 20°C. The main streams where
this happens are ones with less trees
and shrubs around them. (This is
mainly due to clearing of the tall
trees and shrubs which can raise
the temperature by up to 6°C.)
Many waterways with large trees
around them stay at a comfortable
18°C in summer, with some of
the smaller streams staying around
16°C even on the hottest days.
Rising temperatures cause the lobsters
to seek cooler waters. Over a year or so,
this would leave areas which regularly
heat up to 20°C, with no lobsters. This is
especially of concern in smaller waterways.
The bigger river systems such as the Arthur
River would be okay because they have
enough depth to cool the water on
the bottom.
But creeks, such as Big Creek at
Wynyard, parts of the Rubicon River
and Don River would have few lobsters
living in them.
Todd Walsh, the lobster man, says:
“I have never captured a lobster in
Big Creek at Wynyard although I
regularly capture juveniles in other
creeks when I do macro-invertebrate
sampling”.
elp
h
ou ive?
y
n
v
Ca sur
me
Return to: PART 3, Lesson 6 - The Giant Freshwater Lobster - a case study
page 2/2