Cat's Meow

1. Pour 20 mL of milk into a plastic petri dish.
2. Place 4 drops of food color in milk. Vary the location of each drop. Vary the color of each drop. Neon food color works well.
3. Dip a toothpick in dish washing liquid.
4. Touch surface of milk with detergent on toothpick. Do not stir.
5. The milk will swirl. You can see this with the movement of the food color. It is fast and amazing.

Soap has a fat loving end and a water loving end. This is how soap cleanses you. The fat loving end attaches to fat containing grime. The water loving end attaches to water and rinses off of you. The movement of the milk are the attraction of fat in the milk to the soap.

You can have students test the rate of activity with skim, low-fat, whole and half and half milk. Amazingly, the skim moves the quickest.