| A | B |
| states of matter | the physical forms in which a substance can exist; states include solid, liquid, gas, and plasma |
| solid | the state in which matter has a definite shape and volume |
| liquid | the state in which matter takes the shape of its container and has a definite volume |
| gas | the state in which matter changes in both shape and volume |
| surface tension | the force on the particles at the surface of a liquid that causes the liquid to form spherical drops |
| pressure | the amount of force exerted on a given area; expressed in pascals (Pa) |
| change of state | the conversion of a substance from one physical form to another |
| freezing | the change of state from a liquid to a solid |
| freezing point | the temperature at which a liquid changes into a solid |
| melting | the change of state from a solid to a liquid |
| melting point | the temperature at which a substance changes from a solid to a liquid |
| boiling | vaporization that occurs throughout a liquid |
| boiling point | the temperature at which a liquid boils and becomes a gas |
| evaporation | vaporization that occurs at the surface of a liquid below its boiling point |
| condensation | the change of state from a gas to a liquid |
| condensation point | the temperature at which a gas becomes a liquid |
| sublimation | the change of state from a solid directly into a gas |