Next, add about five drops of food coloring to the mixture in the glass, stir and wait a few minutes. Drop the shavings on top of the liquid in the glass. Get a small dab of margarine and roll it in your hands to make a ball. Drop the ball into the glass. Watch what happens to each item that you add.
Food coloring has water in it, so the drops go to the water layer.
You can use the reaction of oil and water to write secret messages. You will need white paper, a white candle or white crayon and watercolor paints. Write a message with the candle or crayon on the paper. It will be difficult because your writing will be invisible. Next, paint over the paper with any color of the watercolor paints.