Why do clouds turn grey when its going to rain?

Answer 1

because they fill up with water

Answer 2

Why Are Clouds Grey

Answer 3

Of course what you see are the photons that pass through or reflect off of the underside of a cloud. When there are only a few clouds in a sunny sky a lot of light reflects off the bottom and appears to be pure white (containing all the colors of the sun's spectrum). When it is about to rain there is less light to reflect up under a cloud with the entire sky filled with wall-to-wall clouds. The rainclouds are not wispy and don't let much light pass through them. The subdued light also reflects from the land (absorbing some color) before reflecting again off the bottom of the cloud. Lastly, the raincloud is filled with billions of tiny perfect spheres of mist and raindrops that diffuse the light and scatter it, as do the raindrops within a rainbow. The photons that finally reach your eye are perceived as gray (or even darker for a thunderstorm).

Answer 4

Because the moisture in the air is condensing. The fact that you can even see clouds is the same principle. The moisture that has evaporated into the air has gotten so concentrated that you can see it.

When it becomes even more concentrated, less light from the sun can get through, which makes them appear darker. This is the same reason you can see rain in the distance as dark 'curtains' over where it is raining.

Quite simply, it is all about how much light can get through, rather than the actual colour of the clouds! Fascinating stuff! I love clouds and stuff. In fact, a great book (it's like 4 dollars) is Pattersons guide to clouds and weather, if you're interested in that kind of stuff (or for schoolwork). You can get it at amazon: http://www.amazon.com/gp/redirect.html?ie=UTF8&location=http%3A%2F%2Fwww.amazon.com%2FPeterson-First-Guide-Clouds-Weather%2Fdp%2F0395906636%2F&tag=weknit-20&linkCode=ur2&camp=1789&creative=9325

Have a good one :-)

Answer 5

They do not change color. What happens is that as they become denser and denser they block out more of the sunlight. Less light makes them appear darker. If you fly an airplane you can climb above the cloud layer and see the bright sunshine on top of the clouds. The tops appear so white it is blinding. Imagine a curtain. It may be light blue but if you put a light source behind it instead of in front it will look darker. If you keep adding more and more layers of curtain behind it it will eventually look very dark and eventually black.

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Answer 6

It is the thickness, or height of clouds, that makes them look gray. Clouds are made of tiny droplets of water or ice. They are formed when water vapor condenses within pockets of rising air. Under the right conditions, the air continues to be uplifted, causing the cloud to build higher and higher.

The tiny water droplets and ice crystals in clouds are just the right size to scatter all colors of light, compared with the smaller molecules of air that scatter blue light most effectively. When light contains all colors, we perceive it as white.

When clouds are thin, they let a large portion of the light through and appear white. But like any objects that transmit light, the thicker they are, the less light makes it through. As their thickness increases, the bottoms of clouds look darker but still scatter all colors. We perceive this as gray. If you look carefully, you will notice that the relatively flat bottoms of clouds are always a little grayer than their sides. The taller the clouds become, the grayer their bottoms look.

Answer 7

Clouds are clear water droplets that look white in the sun. Thick clouds look gray on the bottom because they're so thick they create their own shadow. The thicker, the more water they hold, and the more "ready to burst".
Ever see a gray cloud from a plane?

Answer 8

because well go mix white and blue ok it doesn`t make gray but the water is very heavy if you have a few gallons so that is how much rain a cloud could carry so the cloud gets tense and turns grey hope this helps!.................:)

Answer 9

the droplets of rain held within the cloud no longer allow the light through becasue of the reflection/refraction of light and thus turns dark in color. remember black is the absence of light so that is why it becomes dark out.

Answer 10

The rain water is filling the cloud.

Answer 11

Because when too much water is in the clouds, it changes the color when it drops.