perpetual-motion machine


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perpetual-motion machine,

device that would be able to operate continuously and supply useful work, in violation of the laws of thermodynamicsthermodynamics,
branch of science concerned with the nature of heat and its conversion to mechanical, electric, and chemical energy. Historically, it grew out of efforts to construct more efficient heat engines—devices for extracting useful work from expanding hot gases.
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. A machine that would produce more energyenergy,
in physics, the ability or capacity to do work or to produce change. Forms of energy include heat, light, sound, electricity, and chemical energy. Energy and work are measured in the same units—foot-pounds, joules, ergs, or some other, depending on the system of
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 in the form of workwork,
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.
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 than is supplied to it in the form of heatheat,
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
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 would violate the first law of thermodynamics, which is a special case of the law of conservation of energy (see conservation lawsconservation 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.
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, 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 entropyentropy
, quantity specifying the amount of disorder or randomness in a system bearing energy or information. Originally defined in thermodynamics in terms of heat and temperature, entropy indicates the degree to which a given quantity of thermal energy is available for doing
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 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.
References in periodicals archive ?
The widespread interest in building a perpetual-motion machine was related to the modernizing of society (industrialization, the spread of technology and the development of a new system of values).
Reidel Publishing Company, Dordrecht, 1984, 42-44; Perpetual-motion machines.--Rmt: The Encyclopedia of Science, Technology, and Society, 3.
Many dismiss Newman's ideas as nonsense and his machine as just another impossible perpetual-motion machine. A few, conceding that his ideas are very imaginative, complain that Newman, essentially self taught, fails to present his theory in the "language of physics," that is, in a mathematical form with accepted scientific notation.
Four years in the making, this tale of an inventor of a perpetual-motion machine took the top prize in October at Biarritz, a fest dedicated to Latino cinema.
The third, perpetual-motion machines and clairvoyance, violates the laws of physics--so don't bet on it.
Sure, there are skeptics, even some who believe that TDP will join perpetual-motion machines and alchemy as fanciful and ultimately quixotic panaceas for the real limitations imposed on humanity by finite resources.
For centuries, optimistic inventors have proposed perpetual-motion machines. These would defy scientific law, of course, and none has ever worked as advertised.
Add to that the abuse of congressional power by senators and congressmen who also believe and are wasting hundreds of millions of dollars on ill-conceived medical perpetual-motion machines.
In this way, the policymakers create their perpetual-motion machines, and in this way, McNamara now sets a moral example no less atrocious than in the past.