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Example of a stable and an unstable equilibrium, respectively.
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Stability

Have you ever tried to balance a long stick on your hand? Hard, isn't it? That's because the stick is part of an unstable system. If the wind pushes the stick a little bit, it will keep going in that direction. If you hold the stick upside-down it's much easier to keep straight. That's because when the stick is held from above it's a stable system. If a breeze moves the stick, it will come back to its starting position.

The atmosphere can also be stable or unstable. If it's unstable, then clouds can form. The more unstable the atmosphere is, the more severe the weather could be. Clouds and storms form when pockets of air rise and cool. The air pockets won't rise unless something starts them moving. That's why the air can be unstable but still clear--there's no lifting mechanism to get the air going.


Last modified May 26, 2004 by Jennifer Bergman.

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