Gases, Liquids, and Solids

Gases, liquids and solids are all made up of atoms, molecules, and/or ions, but the behaviors of these particles differ in the three phases. The following figure illustrates the microscopic differences.

Microscopic view of a gas.	Microscopic view of a liquid.	Microscopic view of a solid.

Note that:

• Particles in a:
• gas are well separated with no regular arrangement.
• liquid are close together with no regular arrangement.
• solid are tightly packed, usually in a regular pattern.
• Particles in a:
• gas vibrate and move freely at high speeds.
• liquid vibrate, move about, and slide past each other.
• solid vibrate (jiggle) but generally do not move from place to place.

Liquids and solids are often referred to as condensed phases because the particles are very close together. The following table summarizes properties of gases, liquids, and solids and identifies the microscopic behavior responsible for each property.                                                                                                         

Some Characteristics of Gases, Liquids and Solids and the Microscopic Explanation for the Behavior
gas	liquid	solid
assumes the shape and volume of its container particles can move past one another	assumes the shape of the part of the container which it occupies particles can move/slide past one another	retains a fixed volume and shape rigid - particles locked into place
compressible lots of free space between particles	not easily compressible little free space between particles	not easily compressible little free space between particles
flows easily particles can move past one another	flows easily particles can move/slide past one another	does not flow easily rigid - particles cannot move/slide past one another

                                                                                                 

	change of state