You'll mix food coloring with water at two different temperatures. Measure and pour 1/2 cup of hot water from the faucet into a glass. Then measure and pour 1/2 cup of cold water from the faucet into the other glass. Hold the dropper of food coloring just above the surface of water, and carefully add one drop in the center of each glass. Wait a few minutes and then look at the glasses from the side. Place the white piece of paper behind the glasses to make it easier to see. What do you observe? Is there a difference in how it mixes?