First make the play dough
I used this recipie
1/4 cup of salt
1 cup of flour
and 1/4 cup of warm water
(it came out a little hard but still worked)
Then make into how many different color balls you want. We only used two, and make a hole in them. Then add a couple drops of food coloring inside and gently close the hole.
Give to you'r kid/kids and have them guess what color they think it will be. Once guessing is over let them have fun playing and discovering what color they are.
note- my play dough was dry and the coloring did not stain, but you may want to give you'r kid/kids gloves untill the color is mixed threw out.