Perpetual motion machine: Difference between revisions
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imported>Paul Wormer (Distinguish first and second kind) |
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A '''perpetual motion machine''' refers to a hypothetical machine that keeps operating forever or produces more energy than it consumes. It is considered impossible by the laws of [[ | A '''perpetual motion machine''', also known as a '''perpetuum mobile''' (Latin) refers to a hypothetical machine that keeps operating forever or produces more energy than it consumes. It is considered impossible by the laws of [[thermodynamics]]. | ||
== Thermodynamics == | == Thermodynamics == | ||
In [[thermodynamics]] one distinguishes two sorts of perpetual motion machines. | |||
== Usage in | # A perpetuum mobile of the first kind can conceivably create energy out of nothing, or what amounts to the same thing, it supposedly can increase a given amount of energy without any energy input. A perpetuum mobile of the first kind is in contradiction the the [[first law of thermodynamics]]. The first law states that the amount of energy in the universe is constant, that is, if the energy content of a [[physical system]] seems to increase, this energy must have been transferred from somewhere else, it cannot have been created out of nothing. | ||
It is not uncommon for people to claim to have a perpetual motion machine from which one could generate | # A perpetuum mobile of the second kind is a machine that extracts heat from a body, such as the sea or the earth and converts it into work—i.e., into useful mechanical or electric energy. Subsequently, the work generates heat that is given back to the body in the same amount as was originally extracted from it. This cycle does not violate the first law, but is in contradiction to the [[second law of thermodynamics]]. This law states that it is impossible to extract heat from a single body, and thereby cooling it, without doing work. An air conditioner and a refrigerator need work (usually done by an electric motor) to transport heat from a cold to a warm place. | ||
A perpetual motion machine of the second kind breaks the [[second law of thermodynamics]], which in its common version says "Work is needed to transport heat up a temperature slope". A perpetual motion machine of the first kind that produces more energy than it consumes breaks the [[first law of thermodynamics]], better known as the law of [[conservation of energy]]: "Energy cannot be created nor consumed, only transformed". | |||
== Usage in frauds == | |||
It is not uncommon for people to claim to have a perpetual motion machine from which one could generate mechanical or electric energy. These people are usually very secretive about their work and need sponsors while claiming that the secrecy is to protect them from dangerous entities that might be afraid of gratis energy (usually big oil companies). | |||
== Patent system == | == Patent system == | ||
Since the patent system was put in place, it has received a number of patent requests for perpetual motion machines. The [[U.S. Patent Office]] now requires a working prototype in order to grant a patent for a perpetual motion machine. | Since the patent system was put in place, it has received a number of patent requests for perpetual motion machines. The [[U.S. Patent Office]] now requires a working prototype in order to grant a patent for a perpetual motion machine. | ||
Revision as of 03:02, 18 November 2009
A perpetual motion machine, also known as a perpetuum mobile (Latin) refers to a hypothetical machine that keeps operating forever or produces more energy than it consumes. It is considered impossible by the laws of thermodynamics.
Thermodynamics
In thermodynamics one distinguishes two sorts of perpetual motion machines.
- A perpetuum mobile of the first kind can conceivably create energy out of nothing, or what amounts to the same thing, it supposedly can increase a given amount of energy without any energy input. A perpetuum mobile of the first kind is in contradiction the the first law of thermodynamics. The first law states that the amount of energy in the universe is constant, that is, if the energy content of a physical system seems to increase, this energy must have been transferred from somewhere else, it cannot have been created out of nothing.
- A perpetuum mobile of the second kind is a machine that extracts heat from a body, such as the sea or the earth and converts it into work—i.e., into useful mechanical or electric energy. Subsequently, the work generates heat that is given back to the body in the same amount as was originally extracted from it. This cycle does not violate the first law, but is in contradiction to the second law of thermodynamics. This law states that it is impossible to extract heat from a single body, and thereby cooling it, without doing work. An air conditioner and a refrigerator need work (usually done by an electric motor) to transport heat from a cold to a warm place.
A perpetual motion machine of the second kind breaks the second law of thermodynamics, which in its common version says "Work is needed to transport heat up a temperature slope". A perpetual motion machine of the first kind that produces more energy than it consumes breaks the first law of thermodynamics, better known as the law of conservation of energy: "Energy cannot be created nor consumed, only transformed".
Usage in frauds
It is not uncommon for people to claim to have a perpetual motion machine from which one could generate mechanical or electric energy. These people are usually very secretive about their work and need sponsors while claiming that the secrecy is to protect them from dangerous entities that might be afraid of gratis energy (usually big oil companies).
Patent system
Since the patent system was put in place, it has received a number of patent requests for perpetual motion machines. The U.S. Patent Office now requires a working prototype in order to grant a patent for a perpetual motion machine.