Common examples of solids are wood, sand, ice, bricks and steel. Examples of liquids include water, blood, wine, coffee and rubbing alcohol. Some common gases are hydrogen, helium, propane, water vapor and gaseous nitrogen.
Depending on temperature and pressure, substances can transition from one phase to another. Nitrogen, for example, exists most often as a gas but transitions into a colorless, clear liquid under extremely cold temperatures.
The arrangement and behavior of the particles in a substance differ depending on whether it is in its solid, liquid or gaseous state. In solid matter, the particles are packed very closely together in a regular pattern and do not move from position to position, although they do vibrate in place. This arrangement gives solids a rigid character whereby they do not compress easily and retain a fixed shape and volume.
The particles are also arranged closely together in liquids, but they have no regular pattern and are free to slide past one another. As a result, liquids flow readily and take on the shape of whatever container they occupy.
The particles in a gaseous substance are spaced apart with a great deal of empty space in between them. This causes gases to have neither a definite volume nor a definite shape, so they take on the shape and volume of their containers. The empty space in between the particles makes gases easy to compress.