energio

Energio is the physical quantity that measures the capacity to perform work or to transfer heat. It exists in multiple forms and can be transformed from one form to another, with the total amount remaining constant in isolated systems. The term is cognate with energy in English; in Esperanto, energio is the noun for energy, reflecting the same root from Greek energeia via Latin energia.

Common forms of energio include kinetic energio (motion), potential energio (position in a field), thermal energio (microscopic motion and disorder), chemical energio (bond energy in molecules), electrical energio, nuclear energio, and radiative energio. These forms interconvert, such as chemical energio powering a motor or electrical energio lighting a lamp.

Units and measurement: the SI unit of energio is the joule (J). Larger quantities use kilojoules or megajoules; chemistry often uses calories, while microscopic scales use electronvolts. The work done by a force F along a displacement dx is W = ∫ F · dx, and kinetic energio equals 1/2 m v^2. The rate at which energio is transferred or transformed is power, measured in watts (W), where one watt equals one joule per second.

Conservation and significance: in a closed system energio is conserved, though it may change form. Understanding energio underpins analyses in mechanics, thermodynamics, electromagnetism, chemistry, and biology, as well as the design of engines, electrical grids, and energy-efficient technologies.

History: the concept of energio emerged in the 19th century through the work of scientists such as Joule, Helmholtz, and Clausius, culminating in the general principle of energy conservation that links diverse physical processes.