Clouds are made of water droplets. Pour yourself a glass of water. You’ll notice that the glass of water is not white. It is in fact perfectly clear. Well, glasses of water of big. Maybe tiny droplets are different. Dip a toothpick into the water and get the smallest droplet you can, and put it on a hard surface. You’ll be able to see the surface through the water with equal clarity. Even small drops of water are themselves clear. So if clouds are water, and water is clear, why aren’t clouds clear? They look to us a lot like they reflect light. Light that shines on them bounces off, and when we’re looking at the bottom of clouds on a stormy day we see that most of the sunlight doesn’t make it through the clouds because it has reflected off the tops of the clouds.