why do clouds have flat bottoms?

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  • Anonymous
    1 decade ago
    Favorite Answer

    Clouds are made of ice crystals that form from water vapour carried in the air. Warm air can carry a lot of water vapour, but when the air is cold the water vapour cannot remain as a gas, and turns to ice. You can see this happening when you breathe out warm air with a lot of water vapour on a winter day.

    Cumulus clouds form when warm moist air rises from the ground. As you go higher the air gets colder. When you come to a height where it gets cold enough that the water vapour cannot remain as a gas, it starts to form ice crystals. The flat bottom of a cumulus cloud marks the height where that happens. It marks a particular temperature level in the atmosphere.

    Once it passes that height, the stream of rising air might continue to rise for a while, and then it might start to break up into little eddies, or to move sideways. As it moves it carries the ice crystals with it, and the fluffy tops of the cumulus clouds show the direction the airstream has been moving, and the way the air has been welling and eddying.

  • 1 decade ago

    A cloudbase forms when the temperature and dew point become the same temperature, approaching each other at a rate of 8 degrees C per 1000 m. The level at which they are equal is the condensation level, where relative humidity is 100% and clouds are able to form.

    I won't get into how the clouds form, but because the condensation level will usually be a level surface, the bottoms of clouds tend to be flat (i.e. cumulus clouds).

    As the saturated air rises and the cloud gets bigger, colder drier air gets mixed in with the cloud (entrainment) helping some of the cloud edges to evaporate. So this is why there is more of a puffyness to the cloud edges and top compared to the flat cloud base.

  • Lisa
    Lv 4
    4 years ago

    Answer 1 Many clouds are flat on the bottom because as the air rises from the surface it cools, and at the saturation temperature it starts to condense, which is where the clouds start. Since the whole column is starting at the same conditions and going through the same process, it all condenses at the same height. Answer 2 Clouds are formed when the temperature of the atmosphere reaches the condensation point (this is when it turns to water vapor). When this happens, the water vapor sticks to dust particles in the air and becomes visible. The temperature of the atmosphere usually changes(gets colder) as you go up, so only at a certain point can the water vapor droplets form. When you see the flat bottoms of clouds, you see where this point begins - this is the beginning of the proper temperature for water vapor to form.

  • 1 decade ago

    Warm air rises uniformly from the earth's surface. Clouds begin to form when air gets cold enough to cause water vapor to condense and thus become visible.

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  • 1 decade ago

    the bottom of the clouds is called the ceiling, it is the area in the atmosphere where the temperature and relative humidity are such that watter vapor condenses

  • Anonymous
    1 decade ago

    i dont see that way, clouds have many looks of bottom including like people's bottom.

  • Anonymous
    1 decade ago

    Because the air below is to dense for that certain type of cloud to penitrate...tom science

  • 1 decade ago

    no. they may come rarely. you can see clouds closely if you go top of the mountain, otherwise they don't come down, clouds are generally the form of water.they don't have specific one size.

  • Anonymous
    1 decade ago

    Because only cloud nine is fluffy! LOL

  • 1 decade ago

    They don't. They just appear that way from the angle you are viewing them from and light infraction.

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