Matter: anything that occupies space and has mass, and it is all around us.
Solids, liquids, and gases are the three states of matter commonly found on earth
A fourth state of matter, plasma, occurs naturally in the interiors of stars.
Plasma: a gaseous state of matter that contains appreciable numbers of electrically charged particles .
The presence of these charged particles imparts unique properties to plasmas that justify their classification as a state of matter distinct from gases.
In addition to stars, plasmas are found in some other high-temperature environments (both natural and man-made), such as lightning strikes, certain television screens, and specialized analytical instruments used to detect trace amounts of metals.