Another experiment that I used for 3rd grade is Freezing Oil and Water (it’s my only third classroom and with freezer included, thank you Desayunos Escolares)… Regretfully, I didn’t work like it was supposed to. I don’t know where I went wrong.
The idea was to see the frozen density effect. Normally, oil is on top of water. However when they’re frozen, oil should go to the bottom of the glass.
Try it and tell me your results.