• Question: Why are clouds white?

    Asked by crunchiejelly to Amy, Drew, Julia, Kimberley, Sara on 16 Jun 2011.
    • Photo: Amy MacQueen

      Amy MacQueen answered on 15 Jun 2011:

      Hey! you are full of questions – good work!!! 🙂

      In much the same way as why skies are blue I’m told! Clouds are white because their water droplets or ice crystals are large enough to scatter the light of the seven wavelengths (red, orange, yellow, green, blue, indigo, and violet), which combine to produce white light – so its because of the light they are reflecting. Clouds will appear dark or grey when either they are in another clouds shadow or when the top of a cloud casts a shadow on its own base.

      The darkness of a cloud also depends on the background sky. A cloud will look darker when it is surrounded by a bright sky and lighter when it is in front of darker ones!! And apparently altitude affects it because the higher up the cloud is the more likely it is to contain ice crystals! 🙂

    • Photo: Julia Griffen

      Julia Griffen answered on 15 Jun 2011:

      Clouds are full of water droplets, and well,,, amy’s got the answer there really… no need to exapnd..

    • Photo: Sara Imari Walker

      Sara Imari Walker answered on 16 Jun 2011:

      Nice question! Amy’s got it covered well =) The mechanism is the same as the one we discussed in your great why is the sky blue question? Except clouds have so many kinds of atoms and molecules they absorb all the colors as described by Amy!! So all wavelengths are re-emitted/scattered causing clouds to look white to us (white is the sum of all the other colors). Neat!

    • Photo: Kimberley Bryon

      Kimberley Bryon answered on 16 Jun 2011:

      Amy has answered this really well. Short answer is because they are made of water.

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