perpetual-motion machine definition of perpetual-motion machine in the Free Online Encyclopedia.

perpetual-motion machine, device that would be able to operate continuously and supply useful work, in violation of the laws of thermodynamics Carnot cycle after the French physicist Sadi Carnot , who first discussed the implications of such cycles. During the Carnot cycle occurring in the operation of a heat engine, a definite quantity of heat is absorbed from a reservoir at high temperature; part of this heat is
..... Click the link for more information. . A machine that would produce more energy energy, in physics, the ability or capacity to do work or to produce change. Forms of energy include heat , light , sound , electricity , and chemical energy.
..... Click the link for more information. in the form of work work, in physics and mechanics, transfer of energy by a force acting to displace a body. Work is equal to the product of the force and the distance through which it produces movement.
..... Click the link for more information. than is supplied to it in the form of heat heat, nonmechanical energy in transit, associated with differences in temperature between a system and its surroundings or between parts of the same system.

Measures of Heat

..... Click the link for more information. would violate the first law of thermodynamics, which is a special case of the law of conservation of energy (see conservation laws conservation laws, in physics, basic laws that together determine which processes can or cannot occur in nature; each law maintains that the total value of the quantity governed by that law, e.g., mass or energy, remains unchanged during physical processes.
..... Click the link for more information. , in physics), and is known as a perpetual-motion machine of the first kind. A machine that would completely convert heat from a warm body into work, without letting any heat flow into a cooler body, would violate the second law of thermodynamics, which is concerned with entropy entropy (ĕn`trəpē), quantity specifying the amount of disorder or randomness in a system bearing energy or information.
..... Click the link for more information. changes, and is known as a perpetual-motion machine of the second kind. There were a number of early attempts to design and construct various types of perpetual-motion machines; however, since the 19th cent., when the laws of thermodynamics became understood, most such attempts have been abandoned.