I love trying new things, so when I found new ways to play with milk and colours, I jumped at the chance.
Who knew, when you take a little bit of milk (I used reconstituted powdered instant skim milk here, but Homo works best), dish soap and food colouring you could make a neat reaction?
I had my DD pour a little bit of milk into an old ice cream pail lid, and carefully add a few drops of food colouring to different areas in the milk.
After dipping the end of the toothpick into some dish soap, I had her put it directly into the middle (or close to) of one of the drops of colour, without stirring, and watch what happened to the colours! They "ran away" from the soapy toothpick quickly, making lovely swirls.
She experimented for awhile trying to mix the colours without stirring them. It was really neat to watch her play with this activity, and I'm sure we will try it again when the weather turns cold again.