Gas is one of the four fundamental states of matter .A pure gas may be made up of individual atoms, elemental molecules made from one type of atom or compound molecules made from a variety of atoms. A gas mixture would contain a variety of pure gases much like the air. What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colorless gas invisible to the human observer. The interaction of gas particles in the presence of electric and gravitational fields are considered negligible as indicated by the constant velocity vectors in the image.
Plasma is one of the four fundamental states of matter. It comprises the major component of the Sun. Heating a gas may ionize its molecules or atom. Ionization can be induced by other means, such as strong electromagnetic field applied with a laser or microwave generator, and is accompanied by the dissociation of molecular bonds, if present. Plasma can also be created by the application of an electric field