6th Grade - States of Matter

Solid

A state of matter that has a definite shape and a definite volume.

Crystalline solid

A solid that is made up of crystals in which particles are arranged in a regular, repeating pattern.

Amorphous solid

A solid made up of particles that are not arranged in a regular pattern.

Liquid

A state of matter that has no definite shape but has a definite volume.

Fluid

Any substance that can flow.

Surface tension

The result of an inward pull among the molecules of a liquid that brings the molecules on the surface closer together; causes the surface to act as if it has a thin skin.

Viscosity

A liquid's resistance to flowing. (ex. honey is more viscous than water)

Gas

A state of matter with no definite shape or volume.

Melting

The change in state from a solid to a liquid.

Melting point

The temperature at which a substance changes from a solid to a liquid; the same as the freezing point, or temperature at which a liquid changes to a solid.

Freezing

The change in state from a liquid to a solid.

Vaporization

The change in state from a liquid to a gas.

Evaporation

The process that occurs when vaporization takes place only on the surface of a liquid.

Boiling

The process that occurs when vaporization takes place inside a liquid as well as on the surface.

Boiling point

The temperature at which a substance changes from a liquid to a gas; the same as the condensation point, or temperature at which a gas changes to a liquid.

Condensation

The change of state from a gas to a liquid.

Sublimation

The change in state from a solid directly to a gas without passing through the liquid state. (ex. dry ice)