Absorption and Reflection
This activity will demonstrate that radiation from the Sun (sunlight) can
be converted to heat energy by absorption, and also that solar radiation can
also be reflected.
Time requirement: 50 minutes as an activity, 20 minutes as a demonstration.
- 2 paper cups (not insulated)
- 2 thermometers
- 1 sheet of white paper
- 1 sheet of black or other dark paper
- Wall clock with second hand
- Scotch tape
- Wrap each paper cup with a different color paper. Tape the paper to
the cups if necessary. Make a lid for each cup with the same color paper
as the cup.
- Poke a hole in each lid the same size as the thermometer. Make sure
that the thermometer will fit snugly in the hole.
- Place each cup in direct sunlight and insert the thermometers through
- Observe the temperature of each thermometer while keeping an eye on
- What was the beginning temperature for each cup?
- How long did it take before the temperature in at least one of the
cups began to rise?
- How long did it take for the hottest cup to reach its maximum
- What was the difference in temperature of the two cups after the
temperatures of the cups stabilized?
- Why did the cup(s) heat up?
- Why would one cup have a higher temperature inside?
- Do cars with dark interiors heat up more than cars with light
interiors when they are in direct sunlight? Why???
Last updated: September 02, 1997
Joe Twicken /