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Approach:  Team
Level: Year 8
Focus: Heat transfer and experiment design  
Resources:
3 cups marked A (paper), B (plastic), C (ceramic); paper towels,
measuring jug, 3 thermometers, team answer sheet, stop watch,
jug with very hot water
228Kb
Questions/instructions:  

Boil the jug of water immediately before starting the task. It will cool off a little as students work through the initial part of the task.

Some cups keep liquids warmer for a longer time than other cups. You are going to design an experiment to find out which cup keeps the water hot for the longest amount of time. After you have designed your experiment, you are going to do the experiment.

Show students the equipment, but do not give it to them until after they have designed their experiment.
You will have three cups made from different materials, three thermometers, a stop watch, a measuring jug and a jug of hot water. In your group, design how you will do an experiment to find out which cup keeps the water warm for the longest amount of time. On the answer sheet, write down the steps you will follow in your experiment, and write down how you will keep a record of the results for each cup.

Hand out team answer sheet. Allow time.

1. Before you start to do your experiment, describe to me how you are going to do it.

Give students the equipment (three cups, stop watch, three thermometers, measuring jug and jug of hot water) and caution them on the safe use of the hot water.

Click on graphic to enlarge.

You are going to do your experiment now, taking special care with the hot water, and following your plan. Remember, you will need to have a way of writing down the results for each cup.

Students conduct experiment. Teacher keeps an eye on students’ handling of the hot water to ensure safety.

2. Now tell me the results of your experiment. What is your conclusion from these results?

3. If there were any changes that you made to your plan for the experiment,
explain to me what the changes were, and why you made those changes.
 
% responses
y8
Used water at same temperature
(e.g. pour into cups quickly one after another):
in plan and implemented
36
in plan, but not followed through
6
not in plan, but implemented in experiment
45
not mentioned or done
13
Put the same amount of hot water into each cup:
in plan and implemented
54
in plan, but not followed through
3
not in plan, but implemented in experiment
15
not mentioned or done
28
Time from when water was added:
in plan and implemented
52
in plan, but not followed through
7
not in plan, but implemented in experiment
18
not mentioned or done
23
Took initial temperature in three cups soon after cups were filled:
in plan and implemented
21
in plan, but not followed through
8
not in plan, but implemented in experiment
24
not mentioned or done
47
Took temperatures in three cups at later times after cups were filled:
(recorded time and temperature)
in plan and implemented
58
in plan, but not followed through
4
not in plan, but implemented in experiment
10
not mentioned or done
28
Took at least three temperature measurements in each cup after cups were filled:
in plan and implemented
27
in plan, but not followed through
1
not in plan, but implemented in experiment
7
not mentioned or done
65
Took temperatures in three cups nearly
simultaneously each time temperature was taken:
(or at same interval after filling)
in plan and implemented
42
in plan, but not followed through
1
not in plan, but implemented in experiment
31
not mentioned or done
26
Made table/chart/graph of change in temperature across time:
in plan and implemented
39
in plan, but not followed through
5
not in plan, but implemented in experiment
30
not mentioned or done
26
RESULTS AND CONCLUSION:    
 
Report matches observations:
fully
34
moderately
38
poorly
28
initial drop in temperature when cups are
filled was reported (first temperature recording)
24
report explicitly deals with different rates of cooling
37
report appropriately identifies cup that keeps
water warmest for longest amount of time
53
Ideas for improvement if done again:
two or more useful suggestions
18
one useful suggestion
41
no useful suggestions
41

Total score:
17–21
13
13–16
27
9–12
29
5–8
22
0–4
9
Commentary:
Because this is a team task, no graph of subgroup performance is possible. This was quite a challenging experimental task, complicated by the high thermal mass of the ceramic cup (which caused an immediate drop in temperature when filled). The performances of the teams of year 8 students were very diverse.