History Main / PerpetualMotionMachine

* ''VideoGame/XenobladeChronicles'': The Conduit is described as a true perpetual motion machine, an infinite source of energy with the power to link dimensions and warp reality itself. The scientists working on it used it to create a massive SpaceElevator and an army of HumongousMecha, and this is described almost as a ''side effect'' of its incredible power. One scientist claims that it is the only truly divine thing in the world. [[spoiler:The war over it destroyed the Earth when that scientist, Klaus, activated it without proper safety protocols. The Conduit was controlled by the Trinity Processor, the three parts of which became the three Aegises. In ''VideoGame/XenobladeChronicles1'', Alvis gives Shulk the power of the Conduit so that he can defeat Zanza (which is what Klaus has devolved into over countless eons), and in ''VideoGame/XenobladeChronicles2'' Mythra and Pyra activate their SuperMode of Pneuma to use the Conduit and stop Malos and the Artifices from destroying the world again]].

A Perpetual Motion Machine (also Perpetuum Mobile, Latin for "forever moving") is an old dream of mankind: A machine that creates more energy than it receives from the outside. (A weaker version just keeps moving on and on, without creating new energy you could put in use.) "Free Energy Device" is another name for it.

* The [[http://www.scp-wiki.net/system:page-tags/tag/ectoentropic#pages ectoentropic SCPs]] of the Wiki/SCPFoundation all ''technically'' count as Perpetual Motion Machines, though the ones that merely create matter from out of nothing don't really fit under this trope.[[note]]Since matter is equivalent to energy, creating matter out of nothing is technically creating energy out of nothing.[[/note]]

* It's possible to build an [[ArtificialHuman Automaton]] with a perpetual-motion machine as its power source (the alternative is to build one with a source that needs recharging on a regular basis). However, if it overcharges, it ''will'' explode. Even if it avoids going off, storing too much energy at once can damage its storage systems, reducing how much power it can hold before it detonates. Perpetual-motion Automatons that last more than a few weeks quickly learn to bleed off excess energy at all opportunities.

* ''WesternAnimation/TheSimpsons'', "The PTA Disbands": Lisa is going crazy while the teachers are on strike and creates a perpetual motion machine. Homer later told Lisa that no physics law should be broken in his home.

** ZigZagged in ''VideoGame/PokemonLegendsArceus'' as it's the Poké Balls in [[DistantPrequel that]] game lack the high-tech functions like [[NoConservationOfEnergy changing size]] and are essentially just hollow rocks.

->"And this 'perpetual motion' machine she made today is a joke -- it just keeps going faster and faster."[[note]]Meaning, based on this description, it is now an incredibly destructive bomb."[[/note]]

* In ''VideoGame/CrusaderKingsII'' if you're lucky enough to defy RNG and successfully complete the [[ImmortalitySeeker immortality event chain]], there's a chance another immortal can appear down the line and [[Franchise/{{Highlander}} try to kill you]]. With a high enough Stewardship skill, you can have your guards [[AndIMustScream trap him in a giant hamster wheel for eternity]], giving your capital +20% tax income and -25% build cost & time modifiers.

* The [[http://www.scp-wiki.net/system:page-tags/tag/ectoentropic#pages ectoentropic SCPs]] of the Wiki/SCPFoundation all ''technically'' count as Perpetual Motion Machines, though the ones that merely create matter from out of nothing don't really fit under this trope[[note]]since matter is equivalent to energy, creating matter out of nothing is technically creating energy out of nothing[[/note]].

** [[http://www.scp-wiki.net/scp-3238 SCP-3238]], energy drinks that either make the user burst into flames, become highly radioactive, or turn into a projectile that will quickly leave Earth's orbit, comes with the description "energy from all natural yes [[LampshadeHanging obeys]] [[SuspiciouslySpecificDenial laws of thermodynamics]]."

->"And this 'perpetual motion' machine she made today is a joke -- it just keeps going faster and faster[[note]] meaning, based on this description, it is now an incredibly destructive bomb[[/note]]."

[[folder:Anime and Manga]]
* The Wave Motion Engine in ''Anime/SpaceBattleshipYamato'' and its remake ''Anime/SpaceBattleshipYamato2199''. It functions via extracting vacuum energy from space and converting it into tachyons from which energy can be extracted. It is basically a zero point energy reactor.
* The events of ''Anime/PuellaMagiMadokaMagica'' was based on the attempted creation of such machines. [[spoiler:The incubator are extremely advanced aliens. They want to stop the heat death of the universe, which requires an energy source that can violate the second law of thermodynamics. They figure out how to turn human emotions of pain and misery into an energy source, by turning human girls into magical girls, who then turn into witches, which are in turn hunted by magical girls for the energy collection.]]
[[/folder]]

[[folder:ComicBooks]]
* ComicBook/GastonLagaffe once invented one of the "weak" type. It doesn't do much, it just hops around (and gets on his co-workers' nerves).
* The GadgeteerGenius [[Characters/XMen80sMembers Forge]] dabbled in making one. Never succeeded

[[folder:Film]]
* In ''Film/TheAbsentMindedProfessor'' and its remake ''Film/{{Flubber}}'', Flubber is a perpetual motion substance.
* In ''Film/BattlefieldEarth'', the planet Psychlo has an atmosphere that spontaneously ignites in the presence of radiation. This means radioactive decay does not naturally occur on the planet, meaning the planet ignores the second law of thermodynamics and is effectively a perpetual motion machine.
** In the book, Psychlo's atmosphere has the same implausible property. But, there, it's stated that the Psychlos are actually from a different universe with different physical laws.
* The action-comedy ''Film/KnightAndDay'' revolves around three forces of people trying to secure a prototype Perpetual Energy battery.
* The train in ''Film/{{Snowpiercer}}'' never stops, never needs refueling, and the engine does not appear to be a nuclear reactor. [[spoiler:But while the engine is perpetual, its ''parts'' aren't, necessitating some creative [[HumanResources replacements]] over time.]]
* The animated ''Film/SpacePirateCaptainHarlock2013'' has the Dark Matter Engine for the main ship. An alien technology that gifts the ship the ability to never refuel, rearm or repair.

[[folder:Live Action TV]]

[[folder:TabletopGames]]

[[folder:VideoGames]]

[[folder:WebOriginal]]

--> '''James:''' That machine Paul made that keeps running faster and faster?
--> '''Graham:''' Don't jostle that!

[[folder:WesternAnimation]]

[[folder:RealLife]]

* There's a whole ''gallery'' of plans for these machines -- Donald Simanek's [[http://www.lhup.edu/~dsimanek/museum/unwork.htm Museum of Unworkable Devices]]. Some visitors to this site misinterpret Simanek's motivation as "seeking to eliminate the flaws of such machines so that they can be made workable"; of course, his actual motivation is to educate the public that those flaws are inherent and can ''never'' be eliminated.

*** Perpetual motion machines of the second kind manage to avoid breaking the First Law of Thermodynamics, but do break the Second Law[[note]]Entropy in a closed system always increases over time[[/note]]. Zero-point energy machines generally fall into this, as they do not claim to create energy from nothing, but to exploit energy already in the system...though in doing so attempt to run entropy backwards.

*** Perpetual motion machines of the third kind manage to avoid falling afoul of the Laws of Thermodynamics, and according to classical laws should run forever if left to themselves (such as a planet orbiting a star), but generally some other law of physics (often quantum mechanics) will demand that energy be lost from the system over time.

* In the frictionless vacuum of outer space, it is possible to have an object that will move forever through inertia, as in planetary orbits (which do slow down, but by a negligible amount). Technically, due to conservation of Angular momentum, if you spun a planet in empty space and no force or friction acts against it at all, it would spin forever. However, this is just perpetual ''storage'' of an initial amount of energy. If you hook a generator onto your frictionlessly moving object to achieve the ''production'' of energy that's the whole idea of perpetual-motion machines, all it'll do is tap that initial amount of energy. The object will then slow down, and eventually stop.

* ''Series/{{Mythbusters}}'' tested a bunch of free energy devices. [[RealityEnsues All but one of them completely failed]]. The one that produced any energy was a contraption where liquid in a bunch of tubes connected to a wheel would be heated by the sun, boiling the liquid, causing a shift in the mass of the object, and making the wheel spin. However, it only produced a tiny amount of power, and it wasn't a true perpetual motion machine as it got its power from the sun. Effectively it was an overly complicated and inefficient solar panel.

* Poké Balls in ''Franchise/{{Pokemon}}'' are able to change in size from a ping-pong ball to a baseball, convert Pokémon and items into energy and store them for indefinite periods of time, simulate a "Pokémon-friendly" environment that is "designed for comfort", communicate with a Trainer's Pokédex to automatically log data on captured species, and even ''teleport'' all without a visible power source. They never need to be charged and have been shown in [[Anime/{{Pokemon}} the anime]] to function perfectly after centuries of neglect. Yet [[ReedRichardsIsUseless this revolutionary level of technology is never shown to be applied to other aspects of life]], as humanity relies on conventional forms of energy despite quite literally having perpetual energy in the palm of their hands.

* People attempt to patent Perpetual Motion Machines. Most nations' patent offices can and will reject any at face value, but a few get patented if they are labelled as something else.