1. Fill the glass almost to the top with water.
2. Place the glass so that it is half on and half off the edge of a table, and so that the sun shines directly through the water, onto a sheet of white paper on the floor.
3. Adjust the paper and the glass until a rainbow forms on the paper.
Light is made up of many colors, and when it passes through water, it is broken up into the other colors seen in a rainbow.
