Rainbow Experiment

[35 Minutes]

Celebrate the spectrum of rainbow colors with this experiment. Unlike a real rainbow where the colors and their order is always the same, in this activity every time a new substance is added to the mixture, the colors appear in a different design and order. The addition of liquid detergent into the milk substance breaks the bond of the water molecules or the surface tension. If you do it with different milk substances (whole milk, cream, half and half) the colors will appear different. That's the fun of it!

You'll need:

• 1/2 cup powdered milk • water • liquid detergent • food coloring • cake pan • small pitcher for water • measuring cup

What to do:

1. If possible, print out these directions. Read them through with your child.
2. With your child, gather everything you'll need.
3. Help your child measure and pour 1/2 cup powdered milk into a cake pan. Be sure to cover the bottom of the pan with the milk.
4. Invite her to pour water from a small pitcher into the pan until the pan is 1/2 full. Be careful not to mix the water and dry milk.
5. Challenge her to carefully place several drops of food coloring on the water.
6. Then add a drop of detergent and watch the colors explode.
7. Do variations of this experiment using milk with different proportions of fat, whole milk, half-and-half, and whipping cream. The color will explode and blend in much different ways.

Let's Talk: Ideas to Explore Together.

• When was the last time you saw a rainbow in the sky? What did you think when you saw the rainbow?
• What colors did you see when we added the detergent to the milk?
• What other kind of milk could we use?