Science Activity: Walking Water! Place one or two cups filled with colored water slightly higher than a cup that is empty. Place a strip of paper towel from the top cup, ensuring it touches the bottom, down to the lower cup. Now watch what happens as the paper towel will absorb and siphon the water down into the lower cup. It will take a while, but eventually the entire cup of water will empty into the bottom cup. Try using different colors of water to see what special effects you can make!