As the designated Caretaker Of All Things Pool-Related at our house, yesterday I had to bring the hardness of the pool water up a bit. The product used for this has to be thoroughly dissolved in a bucket of water before being added to the pool, since combining this chemical with water triggers a chemical reaction that releases a lot of heat (i.e., something that you don't want to have happen while the chemical is sitting at the bottom of the pool on your vinyl pool liner.)
As I passed Thing One in the kitchen on my way outside, I asked him if he wanted to come see an exothermic reaction. He cheerfully followed me outside and marveled at how hot the outside of the bucket got while I was stirring the foaming mixture in it with a broom handle.
Then he looked up at me and told me that he was glad I'm a nerd! Gee thanks, kid. :)