What is a Solid?
Solids are one of the four common states of matter - the others are liquids, gases, and plasmas. In general, but not in all specific cases, as the temperature increases and pressure decreases substances pass through the four different states.
The Solid State
The solid state of matter is characterized by the following properties:
- its volume is fixed; it will not expand to fill a container - unlike gases and plasmas
- most solids are incompressible - their volume hardly changes when pressure changes - unlike gases and plasmas
- solids are not fluids, so they cannot flow. Their shapes do not adapt to that of their containers - unlike liquids, gases, and plasmas
- solids are condensed matter, so their volumes are similar to those of liquids, and much smaller than gases and plasmas