The atoms or molecules of solids are still in motion, however they remain fixed in place and vibrate back and forth. In liquids, molecules can move past one another and bump into other molecules, but they remain relatively close to each other. Thus liquids have an undefined shape, but a defined volume. Gases are formed when the energy in the system exceeds the attraction between molecules. In the gaseous state, molecules move quickly and are free to move in any direction spreading out anywhere within their container.
Gases expand to fill their containers and have low density.
Because individual molecules are widely separated and can move around easily in the gaseous state, gases can be compressed easily and they have an undefined shape. Plasmas are hot ionized gases. Plasmas have so much energy that electrons are stripped from individual atoms forming a gas of charged ions . The most common place that plasmas occur is in the center of stars such as the sun. Bose-Einstein Condensates are super cooled materials that exist only within a fraction of absolute zero .