Keeping cool

Keeping cool

Pencil and paperOnline interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about properties that keep things hot or cold.

Question 1Change answer

200 mL of water at 18°C was put into each of four containers. The containers were placed side by side in the sunlight for 10 minutes. The temperature of the water in each container was then recorded.  

Thermometer


200 mL water at 18° C 
Temperature after 10 min
Shiny container 
20°C
Dull container 
23°C
Black container 
24°C
White container 
21°C
 
Use the information from the experiment above to answer the questions.
 
a) Whare is going camping. He wants to paint his water container so that the water inside will stay as cool as possible. 
i)  Should he use black or white paint? blackwhite
ii) Should he use a gloss (shiny) or a matt (dull) paint? gloss/shinymatt/dull

Question 1Change answer

b)  The tank holding the petrol is made out of shiny unpainted metal.
 
 

     Explain why this helps prevent heat absorption.

Question 1Change answer

c)  In hotter climates people tend to wear light coloured clothing. 

     What is the reason for this?
Task administration: 
This task can be completed with pencil and paper or online with SOME auto-marking.
Level:
4
Curriculum info: 
Science, Investigating in science, Physical World
Keywords: 
physics concepts, heat absorption, colour, surfaces, data interpretation
Description of task: 
Task: Identify colours and surfaces that keep things cool. Assessment focus: heat absorption.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.
 
Capability: Use evidence
This resource provides opportunities to discuss what evidence from the investigation supports the students explanations. 
 
Science capabilities: 
Use evidence
Making Better Sense: 
Colour
Answers/responses: 
 

Y8 (05/2004)
a) i)
ii)		 white
gloss/shiny		 very easy
very easy
b)   The shiny metal reflects back any outside heat
(or reverse of).		 easy
c)   Because white/light colours don’t absorb as much heat/reflect more heat
or
dark colours absorb more heat/reflect less heat		 difficult
Diagnostic and formative information: 

For question c) 44% of trial students wrote that dark colours "attract" heat, instead of "absorb" heat. This may be due to an imprecise use of language, rather than a misconception, and can be addressed by discussing the meanings of "attract" and "absorb".
About 11% did not expand on the question. They answered "white keeps you cool"/"dark colours make you warm".

NOTE: These results are based on a trial set of 229 Year 8 students in May 2004.

Ministry of Education (1999). Making Better Sense of the Physical World. Wellington: Learning Media.