Why clouds are dark in color

Why are clouds white?

"... Clouds are made of water droplets and they are transparent," my son wonders.

And a few days ago even my husband asked: "Why are thunderclouds gray or even darker?"

Personally, I find it difficult to answer the question about cloud color in a child-friendly and understandable way. I'll try.

How do we see color?

Colors that we see are nothing more than rays of light in this color that fall into our eye. For example, a leaf is green because it emits green rays of light.

But how does it work? Rays of light mostly come from the sun. The seemingly white rays of light from the sun are a mixture of differently colored rays of light (the rainbow colors, the so-called spectrum). From the multicolored rays of the sun, the leaf swallows all rays of light except for the green ones. It sends these away again and these reach our eyes.

When are clouds white?

Clouds consist of many tiny drops of water. Water is basically colorless and transparent. This means that rays of light actually penetrate water and we would then not be able to see clouds at all. We would only see the sun through the invisible drops of water (comparable to a pane of glass).

On the surface of the many small water droplets, a large part of the light rays are sent away (scattered) evenly from one water droplet to the other until they have finally penetrated the cloud. Then white rays of light from the cloud fall into our eye. These rays of light contain all the necessary information about the clouds so that we can see white clouds.