Activity: The Heat Is On

Children investigate the influence of our Sun as a  heat source  and develop an understanding that different materials store thermal energy with different levels of efficiency.

The Activity
Ask the children what our Sun provides to us on Earth. Light and heat!

  • Do all materials absorb and store the Sun's heat equally? (no)

Invite the children to experiment with the different materials provided. Ask them to fill one cup with sand, one with water, and one with shredded paper.

  • Which one of these materials do they predict will reach the highest temperature when exposed to the Sun's heat?
  • Which will stay hot the longest?

Place the three cups in the box with a thermometer in each cup. Allow a few minutes for the temperature to stabilize, and record the initial temperature.

  • Are the temperatures of the materials equal? (they should be)

Close the box, and put it outside in the sunlight for 30 minutes.

Carefully bring the boxes back inside. Ask the groups to open their boxes and quickly record the temperature for each cup.

  • Which material obtained the highest temperature?

 Have the groups stir the contents of each cup and read and record the temperatures every 2 minutes for 10 minutes. If there is time, have the children graph their temperature recordings.

  • Which material cooled the fastest?
  • Which material retained heat the longest?

Bring the children together to share their findings.

  • Did all groups make the same observations about the different containers?
  • Were their predictions correct?
  • What did the children learn about an object's capacity to store heat?

Discuss how different materials retain the Sun's energy. Conclude from the experiment which material stored the Sun's heat most efficiently, and which one least efficiently.

Lead them in a discussion about how their new information can be applied to their own lives.

  • If they were constructing an energy-saving house, what materials might they choose?

Adapted from Solar Now,



Last updated
January 22, 2007


Ages 10–16

How Long?
60–90 minutes

What's Needed?
For each group of three to four children:

Cardboard box with lid painted black (or with black construction paper taped on)
Three 812-ounce paper cups that will fit into the box
Three thermometers
• A watch with a second hand
Sand, water, shredded paper at room temperature
Pencils or markers and paper for recording observations
Graph paper (optional)
Access to the outdoors and a bright sunny day!

Connections to the National Science Standard(s)

Standards  A&B (grades 5–8):  Communicate an understanding that the Sun’s energy arrives as light with a range of wavelengths, including visible light and  infrared, radiation, and  two ways in which light interacts with matter are  by transmission, absorption.

Standards A, B&D (grades 9–12): Understands  through scientific investigation and effectively communicates that light waves have energy and can transfer energy when they interact with matter.  Understands that our Sun is the major external source of energy.