gas
The gas is one of four basic substance states (the other three are solid, liquid, and plasma, respectively). The gas can consist of a single atom (such as a rare gas), an elemental element (such as oxygen), a variety of elements composed of compound molecules (such as carbon dioxide) and other components. The gas mixture may comprise a variety of gaseous substances, such as air. The significant difference between gas and liquid and solids is that the gas particles are spaced apart. This interval makes it difficult for the human eye to detect a colorless gas. The gas is like a fluid: it can flow and deform. Unlike the liquid, the gas can be compressed. If there is no limit (container or force field), the gas can be spread, its volume is not limited, no fixed. The atoms or molecules of gaseous substances are free to move with each other. The kinetic energy of atoms or molecules of gaseous substances is relatively high. The characteristics of the gas are between the liquid and the plasma, and the temperature of the gas does not exceed the temperature of the plasma. The lower limit of the temperature of the gas is degenerate quark gas and is now more and more important. High-density atomic gas cooled to very low low temperature, according to its statistical characteristics can be divided into Bose gas and Fermi gas, the other phase can refer to the phase list. ...