As I have mentioned before, I am teaching a thermodynamics class at Anderson University. The first few lectures were mostly composed of review. It is important to do such a review, because some concepts are so critically important that I must be sure the students remember them and understand them well. Whenever possible, I like to do demonstrations to help the students visualize the concepts I am trying to get them to understand.
One of my very favorite demonstrations involves something surprising that happens when you burn natural gas in just the right way. It can be used to illustrate several different things, but I used it in my thermodynamics class to illustrate the concept of power. I hope you enjoy it: