So to continue with are heat theme I wanted to do some temperature experiments.
I fond a cool one online, it's where you freeze oil & water together.
First we poured some water into some clear plastic containers, after that I had my kids add some cooking oil. Then you have to leave it for a few minutes.
After a few minutes the oil will have risen to the top of the container (kids thought this was neat). I explained how the oil becomes lighter than the water. Then all you have to do is put the container into the freezer for a few hours.
After it has frozen you, of course, remove from freezer.
Now this is the really cool part; the oil is now underneath the water!!!
Apparently water becomes a solid when it freezes. The water expands when it freezes and becomes less dense that the oil. This causes the water to rise to the top.
In my opinion, this was almost more like a magic trick than a science experiment, just saying ;)