From Citizendium, the Citizens' Compendium
- Physics : The study of forces and energies in space and time.
- Chemistry : The science of matter, or of the electrical or electrostatical interactions of matter.
- Engineering : The profession in which a knowledge of the mathematical and natural sciences gained by study, experience and practice is applied with judgment to develop ways to economically use the materials and forces of nature for the benefit of mankind.
- International System of Units : Metric unit system based on the metre, kilogram, second, ampere, kelvin, mole and candela.
- Density (chemistry) : A measure of the mass per unit volume of a gas, liquid or solid.
- Explosives : Explosive agent; a compound or mixture susceptible of a rapid chemical reaction, as gunpowder, or nitroglycerin.
- Refrigeration : Add brief definition or description
- TNT equivalent : A unit of energy commonly used to quantify the energy released (or "yielded") in explosions.
- U.S. customary units : The units of measurement that are currently used in the United States.