Asked in Meteorology and WeatherCloudsClimatology and Climate Changes
Why do clouds float?
May 11, 2010 12:39PM
They float because they are made of water and ice particles. All together, it's really heavy, more than an elephant. However, it's spread out over a really large area, so it's like an elephant cell. each particle is a micron, .00001 of an inch. a little draft is enough to keep that up, so they stay up because there are a lot of little drafts way up in the sky. It's a good question, and here's why. Clouds are made of water droplets and ice crystals. Together, these droplets and crystals weigh many tons. So if the typical cloud actually weighs as much as an elephant, why doesn't it plummet to the ground? Because unlike an elephant, a cloud's weight is spread out over a very large area. Plus, the cloud's droplets and crystals are very small--about one micron, or one-hundred-thousandth of an inch across. A cloud's individual particles are so small, in fact, that warm air rising from the earth's surface is able to keep them floating in the air. It's similar to how dust motes swirl in a shaft of sunlight. Although the bits of dust are affected by gravity, even the gentlest air currents are enough to keep them dancing around in the air. But clouds don't stay up in the air forever, of course. When the warm air keeping clouds afloat cools, its water vapor condenses and adds to the cloud's droplets. At a certain point the droplets become heavy enough to overwhelm the force of the rising air, and all that water falls to the ground. That's what we call rain!