I first found this idea at Pinterest and when I found a milk sippy cup my 1 year old had hid under the changing table this morning I decided rather than dump it I would let my four year old try this experiment out. All you need is some milk (they say whole milk works best), some dish detergent (I used Dawn), some food coloring and a toothpick (I’ve also seen people say they used a q-tip).
Pour the milk into a plate and let the kids add a few drops of different color food coloring. Dip the toothpick in a little bit of dish detergent and then dip the tip into the middle of the food coloring.
When the detergent disturbs the food coloring it will cause it to spread and make cool designs. My daughter loved watching the colors move by themselves and start to mix with each other. I have to admit I found it pretty cool to watch too.
Of course then she reached the point where she just found it fun to stir up all the colors together. Still this was a great way to get some use out of the milk instead of just dumping it down the drain. With milk prices where they are it breaks my heart whenever I have to dump milk.