If you are lucky enough to have some snow, this is a simple experiment you can use to learn about sunlight and energy. It fits nicely into discussions of solar energy and how energy changes from one form to another.
If you look at the label of any food, you will probably find that it lists the Calorie content. Calories tell us how much energy you will get by consuming the food. How do scientists measure that energy?
This is another of those fun bits of science that many of us think we understand until we really start to look at it, or even better, try to explain it to someone else. Then we reach a point where it becomes obvious to ourselves, and to our audience, that we don't understand it as well as we thought we did.
This experiment is a classic. If I had to pick the one science experiment that I have seen in the most science books, this now would be it. But it is also a very misunderstood demonstration. You will find that even many books of science experiments get the explanation for this one wrong.
This experiment got its start while I was reading Craig F. Bohren's "What Light Through Yonder Window Breaks." It is a book on atmospheric physics, and is written so that you don't have to be a physics professor (or even a physics student) to understand and enjoy it. He writes about the dew that forms on your house windows in the winter, which made me think of other questions about dew drops.
This experiment came from Diane in South-central Pennsylvania. She and her son were discussing ceiling fans, and how they make you feel cooler. They wanted to know if the fan actually cools the room, or does it just feel that way?