On Saturday Cole, dad and I did some science, as usual. Last Saturday the lesson was on: as temperature rises so does volume of stuff, but the stuff is less dense. We also made a thermometer/ barometer out of a graduated cylinder with a sealed cap, a straw that goes through the cap, and an oiled piece of cotton inserted in the straw.
How it works:
The hot air inside the barometer has more volume so it pushes the cotton ball up, but when the air is cold it has less volume causing it to sink.