Why is the sky blue?
What are the states of matter?
Matter comes in five phases, or states. Three are familiar, one is uncommon, and one is a freak of nature that exists only when atoms have virtually stopped moving -- at almost absolute zero. We'll take them from the coldest to the hottest:
Solids are materials with a definite volume and shape. They resist forces that tend to deform them: think ice, steel, or your computer screen.
Liquids are relatively incompressible materials that take the shape of their containers and have a free surface, but do not expand indefinitely: think liquid water, beer or soda.
Gases expand to fill their containers, and usually have relatively low density: think steam, oxygen and laughing gas.
Plasmas are ionized (electrically charged) gases with a similar number of positive and negative charges: think arc welding, fluorescent lights, and the sun.
Did you know?
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