d
ase
yb g
r
i
u
inq rnin
ing nd lea
t
r
a
po
Sup ching
a
te
Heat
Student Name:
Class:
Teacher Name:
School:
Question 1
a)What is meant by the term “change of state”?
Candle wax is heated in a saucepan so that the wax does not
come into direct contact with the heat source. A thermometer is
placed in the saucepan. The liquid wax has a temperature of 80°C.
The liquid wax is poured into the mould and allowed to set.
The graph below shows the change in temperature with time as the
liquid wax set into a solid.
What is happening to the candle wax between A and B on the graph?
The temperature between B and C remains constant.
What, in your opinion, is happening to the candle wax in the mould?
What is happening to the candle wax between C and D on the graph?
Why does the graph level off after D?
From looking at the graph, what do you think the temperature of the room was?
b)
To cool a drink, is it more effective to add water at 0°C or ice at 0°C?
Water
Ice
Explain your answer:
c)On hot days, we sweat or perspire.
Explain how sweating helps to cool the body.
d)
Dogs have fewer sweat glands than humans. The sweat glands are mainly in the pads of
their feet and in their ears. During hot weather, dogs pant and let their tongues hang out
to cool down.
How do these two actions help to keep the dog cool?
Panting:
Tongue hanging out:
Question 2
a)Name the three ways by which heat can be lost from this cup of coffee.
1.
2.
3.
Select two of the ways above and write down how the heat lost by that method could be
reduced.
1.
2.
b)This infra red image shows heat loss from a house.
Different colours represent different levels of heat loss.
Which colour in the photo do you think represents the greatest heat loss?
Explain your answer:
Name two things the owner should do to try and cut down on the heat loss
from this house.
1.
2.
c)Explain how adding milk from the refrigerator to a cup of hot tea reduces the
temperature of the tea.
A
d)An ice cube is trapped at the bottom of a pyrex test tube.
The test tube is then filled with cold water and heated at
the top (A) over a bunsen burner flame as shown. The
Ice
water at the top starts to boil but the ice does not melt.
Why does the ice not melt?
B
What does this tell you about water?
A thermometer was put into the water at A. It was slowly moved down through the water
to the bottom B of the test tube. Using a suitable scale, plot a graph to show what you
predict readings from the thermometer would show as the thermometer went down from
A to B.
Remember: add labels to the axes and add a title to the graph.
Question 3
A student had two temperature probes. She covered probe X with shiny silver paper and
probe Y with dull black paper. She connected the probes to a datalogger.
X
Y
She turned on the electric fire and held the probes at equal distances in front of it for
90 seconds.
The graph below shows the results she got for both temperature probes.
Mark on the graph which line you think is for probe X and which line is for probe Y.
Explain your choices:
What was the temperature of the probes at the start of the investigation?
What was the final temperature of probe X?
What was the final temperature of probe Y?
In Summer, which would be warmer inside, a black car or a silver one?
Black Silver
Explain your answer:
Why do people living in warm countries paint their houses white?
Why do you think that the back of an electric fire is silver in colour?
Question 4
a)Equal volumes of hot water were put in a bright shiny
container and in a dull black one. A thermometer was
placed in each. The temperature of each was taken
every minute and recorded in the table shown below.
Time in
Minutes
0
2
4
6
8
10
12
14
16
18
20
Temperature°C in the
shiny container
80
70
57
48
42
37
30
26
22
21
20
Temperature°C in the
black container
80
62
48
36
30
24
22
21
21
20
20
Draw a suitable chart or graph to show this data.
What was the initial temperature of the water in both containers?
How does the graph tell you which container is losing heat faster?
Using the graph, find the temperature of both containers after 9 minutes.
Black:
Shiny:
What do you think was the temperature of the room in which this experiment was
carried out?
Why were equal volumes of water put into each container?
Which of the containers lost heat the fastest?
What do you think would be the best colour to paint a heating stove in a room?
Explain your answer:
b)Mary, John and Pat are wondering if
putting an overcoat on a snowman
would melt him quicker or make him
last longer.
Read what each of them is saying.
Who do you think is correct?
Mary
John
Pat
Don’t put the coat
on the snowman it will melt him
I think it will keep
him cold and stop
him melting
John
Mary
I don’t think the
coat will make
any difference
Give a reason for your answer:
Pat
You want to carry out an investigation in the laboratory to check if your answer is right.
Write a report, using the headings provided, to explain how you would carry out this
investigation in the science laboratory.
Plan.
Diagram of the Apparatus to be used.
Data to be collected.
How I would arrive at a conclusion.
For teacher use only.
Comment:
How to improve: