Phases of Matter

Matter can exist in several distinct forms which we call phases. The most familiar phases are solids, liquids and gases. Whether a substance is a solid liquid or gas depends on:

• the forces holding the particles together and
• the energy of the moving particles.

==Solid Phase==

The particles are closely packed and are held together by strong forces of attraction. the particles vibrate in fixed positions and cannot move past each other.

==Liquid Phase==

As a substance is heated, the energy of the particles is increased, and they are no longer tied to their fixed position but have the energy to break the forces of attraction between them and can move relative to each other although they are still closely packed together.

==The change from solid to liquid is called melting and from liquid to solid is freezing.==

==Gas Phase==

If a substance is heated further away, the energy of the particles is increased so much that they break away from each other and move further apart. They are no longer in fixed positions and there are spaces between the particles.

==The change in phase from liquid to a gas is called evaporation or boiling and a gas to a liquid condensation.==

==The phase change from solid to a gas is called sublimation.==