My students often stare in wonder at the radiometer that sits in the window sil of my classroom. A lot of them think it's the temperature that causes the different spinning rates. Others think it's the amount of light. I decided to attempt to see which factor determines it. This could be a good inquiry activity for students and it also demonstrates how smartphones are becoming useful data collection devices.
References allow you to track sources for this article, as well as articles that were written in response to this article.