They offer a more intense color than liquid dyes and must be added in small, controlled quantities. You can also buy powdered food coloring -- a dry food-grade dye that doesn't have any additives.

In the activity below, you can try chromatography to separate colors in a mixture of food coloring! Place a coffee filter on a tray or newspaper. In a small plastic cup, add 2 drops of green food ...

1. Carefully pour some milk in a dish so it just covers the bottom. 2. Gently add one or two drops of red, blue, and yellow food coloring to the same spot in the center of the milk. 3. Dip a cotton ...