Science Buddies: "Ask an Expert"

Hi! I am working on a project and the question is "How does color affect heating by absorption of light?" The guidelines given by my science teacher asked for a control group and experimental groups. I made the experimental group jars with black and white construction paper, but what would the control group be?
Thanks!

Hello s_chen,

The choice of a control depends on what you are measuring. The result you obtain from the control is a reference to compare to each of the other results.

Each color of paper will lead to a different temperature rise. You might compare that rise to the rise of a jar with no paper on it. You might compare each colored paper test to placing the jar in the position you use for the time you use, but not turning on the light.

Choose a control that you think is as nearly the same as your colored paper tests but doesn't have the feature you're measuring.

Suppose you ran a test with the light turned off, but you still saw a temperature rise. That would be unexpected, and it would suggest to you that some neglected factor is disturbing your experiment, and you would want to identify that factor and remove it. Perhaps the test setup is near a radiator, and it's the radiator that's heating up the jar. Solution: move the setup away from the radiator.

Good luck, WW