Exploding Coffee: What is Heat?

Demonstration I use in my introduction to thermal energy. I use it in order to get students to think about what heat really is. Prior to the video, I ask students if adding sugar to my coffee (which I am sipping in front of the class) will make it explode. They typically roll their eyes and say no. I go on to tell them that I found a way to make my coffee explode and I have filmed it for them. I show them the video and we discuss WHAT exactly has happened. I like using a freyer group model and getting students to deduce that heat is movement of molecules. Therefore, when you are adding MORE molecules to the hyper movement of hot liquid, it "explodes".