States of Matter
Solid, Liquid, Gas, & Plasma
There are FOUR main states of matter.
The terms solid, liquid, gas, and plasma refer to states of matter. Each state of matter has certain characteristics.
Solid, Liquid, Gas, and Plasma
Solids have a definite volume and have molecules that stay in a rigid position. These molecules vibrate in place. Molecules in liquids slide past each other easily. Liquids take the shape of their container and have a definite volume. Gas molecules flow freely and will expand to fit their container. Therefore, they do not have a definite volume. Finally, plasma is a state in which particles are ionized.
Changing states:
At certain temperatures, adding or removing thermal energy will cause matter to change from one state to another.
Boiling
Heating a liquid will eventually vaporize it into a gas. The boiling point is the temperature at which a liquid becomes a gas.
Condensation
Cooling a sample of matter, which involves the removal of thermal energy, causes the opposite changes of state. Condensation is the change from gas to liquid. The condensation point is the temperature at which a gas becomes a liquid.
Freezing
Freezing is the change from liquid to solid. The freezing point is the temperature at which a liquid becomes a solid.
Melting
Heating a solid will eventually melt it into a liquid. The melting point is the temperature at which a solid becomes a liquid.
Sublimation
When a solid turns into a gas without first becoming liquid, it is called sublimation. For example, the surface layer of snow or ice (solid water) may turn to fog or steam (gaseous water) without first melting into liquid water.
Deposition
When a gas turns into a solid without first becoming liquid, it is called deposition. For example, the water vapor in humid air may form frost (solid water) on a cold window without first condensing into liquid water.