When The Heat's On, Colour Counts

The effect of colour on heat absorption. This activity relates to the Greenhouse Effect and complements a study of the production of electricity using brown coal.

CSF Science - Natural & Processed Materials, Level 4
Identify factors that determine the choice of materials for particular purposes, including suitability of fuels.

Introduction
Saving the energy used to artificially heat and cool our surroundings would lead to a significant reduction in greenhouse gases. Understanding what contributes to the natural heating and cooling effect of the sun is a step toward energy efficient thinking.

Relevance to the CSF
A learning outcome of Level 4 SCIENCE is the ability to describe or discuss how the properties of natural and processed materials affect their use.

Student learning objectives
Understanding the effect of color on heat absorption.

Materials

food dye
ice cube tray
ruler
plate to catch water

What to do
Fill some ice cube trays with water to the same depth. Add different colors and concentrations of food coloring to different cubes. Stir well. When the ice cubes freeze, you should have a collection of cubes in a variety of colors. Set them out in the sun and measure the height of each ice block at regular intervals until they have all melted. Choose an interval that suits the temperature of the surroundings.

Discussion points

Is there a connection between color and heat absorption?
What might be the implications for energy conservation?

Further investigation
Use a magnifying glass to focus sunlight on a piece of black construction paper.
How long does it take before the paper starts to smoke?

Repeat the procedure using white construction paper.
Does it take more or less time to start smoking? Why?

Follow up
You could make a display or posters to educate people about the importance of colour in keeping cool. Draw a picture of two people one dressed in white and the other dressed in black. Try to show how each would feel if they were standing in the sun.

Learning technologies
Use the internet to find out about the color of clothing worn in countries with hot or cold climates. Develop an email link with students in a country with extreme climate to talk about the use of colour in a different culture.

For more information contact MEV