The fourth state of matter is plasma. We are familiar with one more word besides solid , liquid and gaseous. This is called 'plasma'. This is also a state of matter. All four conditions depend on the internal temperature of the substance. Plasma conditions are not usually detected in our eyes. From solid to liquid the temperature or energy is higher. The heat and energy from the liquid vapor is more. When heat energy is too high or at very high temperatures the substance turns into plasma. In this state, molecules of matter are converted into electrons , protons and neutrons. In other words, gaseous molecules are volumetric. Plasma conditions are not usually detected in our eyes. However, in neon sign , fluorescent light (tube light , energy bulb) the gas atom is in ionized or plasma state. Plasma conditions are predominant in the outer universe. Plasma state of the Sun and most stars , the polar matter visible at the North Pole. Plasma torches are used in industrial plants.