You will need nail polish, water and black paper.
Let a single drip of nail polish fall into a container of clear water. Quickly place a piece of black paper on top. Lift the paper and turn it over to see what happened.
A rainbow!
You may have a problem if you take too long to put the paper on the nail polish.
If you wait too long the nail polish will form a skin on the water.
Don’t worry because you can still use it.
Slip the paper under the skin and lift it up.
We only used black paper but after seeing this child’s rainbow,
which he made on paper painted green, we should have tried a variety of colours.
To check out where I found this idea visit The Science Kiddo.