Matter can exist in four main forms - solid, liquid, gas, and plasma - depending on how tightly or loosely the atoms are packed together. Solids have closely-packed atoms, liquids have loosely-packed atoms, gases have widely-separated atoms, and plasma consists of free electrons in space. There are also some less common forms of matter like super solids, which are frictionless. The document provides an overview of the basic properties and forms of matter.