Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas or atomic gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide). 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.
The gaseous state of matter is found between the liquid and plasma states, the latter of which provides the upper temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention. High-density atomic gases super cooled to incredibly low temperatures are classified by their statistical behavior as either a Bose gas or a Fermi gas. For a comprehensive listing of these exotic states of matter see list of states of matter.
Famous quotes containing the word gas:
“Shielded, what sorts of life are stirring yet:
Legs lagged like drains, slippers soft as fungus,
The gas and grate, the old cold sour grey bed.”
—Philip Larkin (19221986)
“Papa died in the gas chamber,
slipping blue as an undressed minnow,
gulping in the shower to wash the Jew off him.”
—Anne Sexton (19281974)
“When we can drain the Ocean into mill-ponds, and bottle up the Force of Gravity, to be sold by retail, in gas jars; then may we hope to comprehend the infinitudes of mans soul under formulas of Profit and Loss; and rule over this too, as over a patent engine, by checks, and valves, and balances.”
—Thomas Carlyle (17951881)