Energy, from the Greek energeia or activity, denotes the capacity of acting or being active. Aristotle used the term to denote the activity of tending toward or enacting a goal, which differs from the modern understanding of energy as the capacity to do work. To a certain degree energy functions as the abstract equivalent of fire, one of the Aristotelian four elements. The modern concept of energy can engender either physical or psychological activity and be analyzed in one or more of three senses: scientific, technological, and ethical.

Science of Energy

In modern science, the term energy has become a precise technical concept with such distinctions as kinetic (energy related to the motion of a body) and potential (stored energy of position). Other important distinctions pertain to the different forms of energy, including thermal, mechanical, electrical, chemical, radiant, and nuclear.

The history of the modern science of energy...