Water Phases
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Time to use your imagination

COLD

Imagine a bunch of people standing around in the cold. What are they doing? Most likely they will bunch together for warmth. They'll probably be bundled up and shivering. You won't see a whole lot of people skipping or running. Molecules also bunch up when it gets cold, but for different reasons. When molecules have very little energy, they don't bounce around a lot. They tend to stay in place, making that group of molecules solid. Solids have low energy and don't move a whole lot.

WARMER

As people warm up, they get more active. Imagine those people who were all bundled together, and picture what they'll do when it gets warmer. Most likely, they will get rid of the coats and spread out a bit. The people get more active and do more activities. Molecules, as they get more heat energy, bounce around a bit more. They don't stay in tight formation, but bounce across each other a bit. They don't have enough energy to bounce away completely, but they move quite a bit. When a group of molecules have enough evergy that they don't keep their shape, but don't leave completely, we say that substance is a liquid.

HOT

What do people do in the summer? They're no longer confined to school, and often go on vacation. People don't like huddling together when it's hot either, but sprawl out a bit. Molecules, when they get a lot of heat energy, start spreading around. They may bounce away from the other molecules completely. When a group of molecules behave this way, we say it's a gas. Gasses have a lot of space between the molecules. There is so much space that a gas doesn't have a specific size or shape, and the particles may expand to fill a whole room. That's a big vacation for the molecules.



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