Watching Water

I've got several big projects still ongoing, but we've been doing some more little things this week.  Yesterday we did another science experiment to demonstrate that heating molecules makes them move faster.  We talked about how the molecules move in a solid, a liquid and a gas, and discussed why this is (answer: heat is a form of energy so as you heat a molecule it has more energy and is able to move faster)

Anyway, the following experiment demonstrates this beautifully.

Step 1

 Take two clear containers (makes sure they are heatproof - you don't want boiling water all over your children!) and fill one with tap water and the other with boiling water.

Step 2

 Put a couple of drops of food colouring in each one - make sure you put the same amount in each, and as close to at the same time as possible.

Step 3

 Watch what happens - the food colouring in the boiling water glass will mix in because of the movement of the water, whereas the food colouring in the tap water will not mix in as well because the molecules are far less active.