Energy (physics)

Energy () is the quantitative property that is transferred to a body or to a physical system, recognizable in the capacity to do work and in the form of heat and light. Energy is a conserved quantity—the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement for energy in the International System of Units (SI) is the joule (J).

law of physics and chemistry

energy held by an object because of its position relative to other objects or stresses within itself, rather than its velocity

physical law relating mass to energy

repulsive property with constant energy density theorized to make up most of the universe’s energy content to account for its observed expansion

Enthalpy () is the sum of a thermodynamic system's internal energy and the product of its pressure and volume. It is a state function in thermodynamics used in many measurements in chemical, biological, and physical systems at a constant external pressure, which is conveniently provided by Earth's ambient atmosphere. The pressure–volume term expresses the work W that was done against constant external pressure P_\text{ext} to establish the system's physical dimensions from V_\text{system, initial}=0 to some final volume V_\text{system, final} (as W=P_\text{ext}\Delta V), i.e. to make room for

energy contained in a system, excluding energy due to its position as a body in external force fields or its overall motion

potential and kinetic energy associated with the position and movement of a physical object

lowest possible energy of a quantum system or field

mass of a physical system independent of its motion; equals its total mass when at rest

forms of energy

quantum physical phenomenon

scalar potential that describes a gravitational field

concept in thermodynamics

Bioenergetics is a field in biochemistry and cell biology that concerns energy flow through living systems. This is an active area of biological research that includes the study of the transformation of energy in living organisms and the study of thousands of different cellular processes such as cellular respiration and the many other metabolic and enzymatic processes that lead to production and utilization of energy in forms such as adenosine triphosphate (ATP) molecules. That is, the goal of bioenergetics is to describe how living organisms acquire and transform energy in order to perform bi

random change in the energy inside a (typically sub-microscopic) volume

background energy existing in space

process of changing energy from one of its forms into another

physical quantity representing energy content per unit mass

concept in physics

graphical description of a physical dynamic system

hypothesis that the total amount of energy in the universe is exactly zero

minimum kinetic energy a pair of particles must have when they collide in order to produce a given particle

measure of the excess specific energy over that required to just barely escape from a massive body

Contribution to the total energy caused by interactions between entities present in the system

lowest-energy state

mathematical transformation in physics that moves the times of events through a common interval

theorem in general relativity