PERPETUAL MOTION: AN IMPROBABLE
(Investigator 145, 2012
machine is an imaginary device that, once set in
motion will continue to operate indefinitely. The illustration in
Figure 1 of an overbalancing wheel mechanism is based on a drawing from
the notebooks of Villard de Honnecourt (1235), and is testimony to the
antiquity of the idea. The underlying assumption is that the weighted
arms fall in the direction of the turning wheel (as indicated by the
arrow) thereby ensuring one side is always heavier than the other, thus
engendering a continuous rotary motion. The purpose of this essay is to
explain why this and other devices claimed to be perpetual motion
engines will not work.
of nature forbid the possibility of
constructing perpetual motion machines, of which there are three types:
first type of
perpetual motion machine is one whose efficiency is
claimed to exceed 100%. In other words the inventor claims it creates
energy from nothing. An example of this kind of device is Garabed
Giragossian's flywheel (1917). This engine consisted of a huge flywheel
that was hand-cranked by an assistant, and then kept in motion by an
device used to measure the power output of a
machine), Giragossian measured the energy needed to bring the flywheel
to a stop and found that it was 200 times greater than what the
electric motor supplied.
Giragossian failed to realize there is a difference
between power and energy (energy is the measurement of the capacity to
perform work, whereas power is the rate at which work is performed).
The energy supplied by his assistant's muscles and the electric motor
was stored as kinetic energy in the flywheel as it was brought up to
speed over time, and when the flywheel was brought to an abrupt stop,
the stored energy was instantly expended.
machine of the first kind cannot work because it
attempts to violate the First Law of Thermodynamics that states, in
part, that matter and energy can neither be created nor destroyed,
merely transformed (the conservation of matter and energy).
second kind of
machine is one that the inventor claims will take
heat from the environment and convert it wholly into work. An example
of this kind of device is Professor John Gamgee's Zeromotor (1880).
This engine was supposed to operate in the following way: A reservoir
of ammonia, which boils at minus 33° C, would be vaporized by
ambient heat producing a vapor pressure of four atmospheres that would
drive a piston. As the vapor expanded it would also cool, condense and
be returned to the reservoir for the next cycle.
kinds of engine
will not work because whatever working fluid is
used cannot expand to the point of condensation due to the resistance
of the piston. Furthermore, the Second Law of Thermodynamics (in
Clausius' formulation) states that heat cannot be transferred from a
colder to a hotter body. Consequently, in order for the working fluid
to be condensed, it must be cooled by refrigeration, which requires
more energy than what the engine is capable of generating.
third type of
perpetual motion machine is one that does no work but
merely continues in motion forever. An example of this kind of device
is shown in Figure 1.
Law of Thermodynamics does not permit the
operation of these kinds of engine because energy is always lost
through the conversion of kinetic energy (the energy of motion) to heat
energy through friction generated by the moving parts. In the absence
of a continuous power source all machines, like spring driven clocks,
will eventually run down. Entropy — the measure of the unavailable
energy of a system and its resulting disorganization — increases over
creators of perpetual
motion machines are, generally speaking,
individuals who have little, if any, sound understanding of physics.
Rather, they are usually backyard inventors with some practical
knowledge of mechanics and a boundless sense of self-confidence in
their own ability. This is a potentially dangerous combination.
sincere in his belief that the machine will work, he
may waste large sums of his own and other people's money in pursuit of
an impossible dream, thus running a considerable risk of financial ruin
for himself and his investors. When the inventor realizes that the
machine will not work, what started out as a delusion may degenerate
into outright fraud — having to admit he was wrong may be deemed too
humiliating, especially when fantastic promises have been made and
other people's money is involved.
the history of
perpetual motion is littered with examples of
outright fraud. For example, in 1813 Charles Redheffer of Philadelphia
displayed (for a fee) what he claimed was a perpetual motion machine
whose main component was a large gearwheel driven by a small pinion.
The secret of the device's continued operation, however, lay not in
some esoteric energy, but in the power of a hidden clock spring.
fifty years later
John E. W. Keeley fleeced those who invested in
his Hydropneumatic Pulsating Vacu-engine, a complicated mechanism of
pipes, valves, metal globes, nozzles and gauges that allegedly
converted water into 'inter atomic ether.' Unfortunately, it was only
after his death that investigators discovered the device was powered by
compressed air carried in concealed pipes.
recent example of
perpetual motion is Joe Newman's Energy
Machine, a kind of generator that he claims produces more power that it
takes to run. Newman, a self-taught man, appears to have made the
mistake of thinking that by continually increasing the number of turns
of copper wire around the armature of an electric motor, a point would
eventually be reached where the motor would produce more power than
what it would take to run. Unfortunately, this is not possible:
ended up with
was a motor that ran on a very small current —
but a huge voltage was needed to supply that current. Since the power
drawn by the motor is given by the product of the current and the
voltage, the increase in voltage, as you would expect from the law of
conservation of energy, just offsets the lower current. There is no
increase in efficiency." (R. Park: Voodoo Science, page 102)
the 1986 US Senate
hearing concerning the Patent Office's
refusal to grant him a patent, Newman refused to have the device
tested when his claims were challenged. If it worked why refuse the
test? Perhaps it is because patents will only be granted if the
applicant submits a working model of the device that can withstand
scientific scrutiny. Needless to say, this has not happened to date.
of nature do not
permit the possibility of perpetual motion
machines because energy can be neither created nor destroyed, merely
transformed, and what energy does exist is always dissipated due to
friction. Consequently no system can remain in operation forever. This
also applies to celestial bodies whose motions are subjected to
dissipative forces such as tidal friction and gas friction as they move
through the extremely tenuous interstellar dust and gas that exists in
space. Indeed, the entire universe is winding down — as it cools
entropy increases due to the unavailability of energy and eventually
all things will come to an end. Perpetual motion, like eternal life, is
an impossible dream.
Bernal, J.D. Science
in History, Vol. 1 The Emergence of Science,
Penguin Books, England, 1969.
Grant, J. A. Directory
of Discarded Ideas, Corgi, London, 1981.
Park, R. Voodoo
Science, Oxford University Press, Oxford, 2000.
Pyke, M. Dr Magnus
Pyke's Dictionary of Fallacies, Willow Books,
Yule, J.D. (Ed.) Concise
Encyclopedia of Science and Technology,
Crescent Books, New York, 1985.
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