For this experiment you will need some red, yellow and blue food coloring, some hot water, cold water, an ice cube tray and some clear plastic cups. Use the food coloring to make some red, yellow and blue ice cubes. Next fill the cups half full with the warm water. Instruct the children to then put two different colored cubes into the cubes and observe what happens. The cubes should melt together forming a completely new color. To make the experiment more interesting add a third cube to the mixture to form another color.
This experiment is extremely simple requiring no more than a small mirror, a shallow bowl full of water and a window that gets plenty of sun. Submerge the mirror into the bowl full of water. Then move the bowl to the window and arrange the mirror so that the sun's rays hit it. Try to then reflect the rays onto a wall or ceiling producing a rainbow pattern.
Take some red, blue and yellow food coloring, a cup of milk, some dish soap and a shallow bowl. Next instruct the children to pour the milk carefully into the bowl. Once it has settled they then need to add three drops of red coloring at one edge of the bowl, three drops of blue a third of the way around and three drops of yellow another third of the way around. Once completed ask them to squeeze a drop of soap into the center of the bowl. Instead of sinking to the bottom or mixing with the milk, the soap will float on the top of it and spread over the surface. As it does this it will combine with the food colors, mixing them together forming new colors.
You'll need some white carnations, several vases, some water and some food coloring for this next experiment. Fill the vases close to the top with water and then add plenty of food coloring so that the water turns a dark color. Next cut the stem of the carnation at the bottom. Instruct the children to put the carnation into the colored water and then leave for a few days in a safe place. After a couple of days the carnation will have changed to match the color of the water.