Electrical muscle stimulation is a process with which the low-level electrical currents are used to stimulate the muscles and forces them to contract. The Food and Drug Administration, which regulates the devices performing these functions says that such devices are often marketed illegally and used as shortcuts for muscle building and definition. It says that using it for building six-pack abs is not the main purpose of its use and it is regularly used for therapeutic purposes instead, which is its main purpose.
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 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. One type of commonly known gas is steam.