Perpetual motion is a body movement that continues indefinitely. The perpetual motion machine is a hypothetical machine that can work seamlessly without any energy source. This kind of machine is not possible, because it would violate the first or second law of thermodynamics.
This thermodynamic law applies even on a very large scale. For example, the movement and rotation of celestial bodies such as planets may seem eternal, but are in fact subject to many processes that slowly eliminate their kinetic energy, such as solar wind, intermediate interstellar resistance, gravitational radiation and thermal radiation, so they will not continue move forever.
Thus, machines that extract energy from finite sources will not operate indefinitely, because they are driven by energy stored at the source, which will eventually run out. A common example is a device powered by ocean currents, whose energy is essentially from the Sun, which will eventually burn. Machines supported by more vague sources have been proposed, but are subject to unavoidable laws, and will eventually end.
By 2017, new materials, time crystals, are found where on the microscopic scale the component atoms are constantly repeated, thus satisfying the literal definition of "eternal motion". However, this is not a perpetual motion machine in the traditional sense or breaking the laws of thermodynamics because they are in the state of their quantum soil, so no energy can be taken from them; they have "motion without energy".
Video Perpetual motion
History
The history of immortal motion machines dates back to the Middle Ages. For thousands of years, it is not clear whether the immortal instruments were possible or not, but the development of modern thermodynamic theory has shown that they are impossible. Nevertheless, much effort has been made to build such machines, continuing into modern times. Modern designers and supporters often use other terms, such as "over unity", to describe their findings.
Maps Perpetual motion
Basic principles
Oh you seekers after the eternal movement, how many chimera are you wasted on? Go and take your place with the alchemists.
There is a scientific consensus that perpetual motion in an isolated system violates the first law of thermodynamics, the second law of thermodynamics, or both. The first law of thermodynamics is the legal version of conservation of energy. The second law can be expressed in several different ways, the most intuitive being that heat flows spontaneously from a warmer place to a cooler place; relevant here is that the law observes that in any macroscopic process, there is friction or something close to it; Another statement is that no heat engine (a machine that produces work while moving heat from high temperature to low temperature) can be more efficient than a Carnot heat engine.
In other words:
- In an isolated system, one can not create new energy (energy conservation laws). As a result, thermal efficiency - the resulting workability divided by input heating power - should not be greater than one.
- The output power of the heat engine is always smaller than the input heater power. The rest of the heat energy provided is wasted as heat to the surrounding environment. Therefore thermal efficiency has a maximum, given by Carnot's efficiency, which is always less than one.
- The actual heat engine efficiency is even lower than Carnot's efficiency due to the irreversibility arising from the speed of the process, including friction.
Statements 2 and 3 apply to hot machines. Other types of machines that convert for example mechanics into electromagnetic energy, can not operate with 100% efficiency, because it is impossible to design systems that are free of energy dissipation.
Machines that adhere to both laws of thermodynamics by accessing energy from unconventional sources are sometimes referred to as perpetual motion machines, although they do not meet the standard criteria for the name. For example, clocks and other low-power machines, such as Cox watches, have been designed to run at differences in barometric pressure or temperature between night and day. These machines have an energy source, though one that is not easily visible so they just seem to violate the laws of thermodynamics.
Even machines that extract energy from long-lived sources - like ocean currents - will be depleted when their energy source will do it. They are not perpetual motion machines because they consume energy from an external source and not an isolated system.
Classification
One classification of perpetual motion machines refers to certain thermodynamic laws that the machine claims to infringe:
- The perpetual motion engine of the first type produces work without energy input. Thus breaking the first law of thermodynamics: the law of conservation of energy.
- second type immortal motion machine is a machine that spontaneously converts heat energy into mechanical work. When heat energy is equivalent to the work done, this does not violate the law of conservation of energy. However, it violates the second law of refined thermodynamics (see also entropy). A signature of a second type immortal motion machine is that there is only one heat reservoir involved, which is spontaneously cooled without involving heat transfer to a cooler reservoir. This heat conversion becomes a useful job, with no side effects, impossible, according to the second law of thermodynamics.
- A third type immortal motion machine is usually (but not always) defined as one that completely eliminates friction and other dissipative forces, to maintain motion forever (due to mass inertia). ( Third in this case refers only to the position in the above classification scheme, not the third law of thermodynamics.) It is impossible to make such a machine, because the dissipation can never be completely mechanically removed. system, no matter how close the system achieves this ideal (see example in the Low Friction section).
Not Possible
"Epistemic impossibility" describes things that really can not happen in the current legal formulation . This "impossible" word interpretation is what is meant in the discussion of the impossibility of perpetual motion in a closed system.
Conservation laws are very strong from a mathematical perspective. Noether's Theorem, which was proved mathematically in 1915, states that any law of conservation can be derived from the continuous symmetry of the action of the physical system. For example, if the correct laws of physics remain invariant over time then energy conservation will occur. On the other hand, if the conservation law is invalid, then the physical foundation needs to be changed.
Scientific investigations of whether the laws of physics invariant over time use telescopes to examine the universe in the past to find, to the extent of our measurements, whether ancient stars are identical with today's stars. Combining various measurements such as spectroscopy, direct measurement of the speed of light in the past and similar measurements suggests that physics remains essentially the same, if not identical, for all observable time spanning billions of years.
The thermodynamic principles are so well established, both theoretically and experimentally, that the proposals for the eternal motion machine universally meet with mistrust of the physicist. Any proposal of perpetual motion design offers a potential instructive challenge for physicists: one believes that it can not work, so one has to explain how it failed to work. The difficulty (and value) of such an exercise depends on the subtlety of the proposal; the best tend to arise from the experiments of physicist's own thinking and often explain certain aspects of physics. So, for example, the mind experiment of the Brownian rocket as the eternal propulsion engine was first discussed by Gabriel Lippmann in 1900 but only in 1912 Marian Smoluchowski gave an adequate explanation of why it did not work. However, during those twelve years scientists did not believe that the machine was possible. They just do not realize the exact mechanism that will fail.
The law that entropy always increases, in my opinion, the highest position among the laws of Nature. If someone shows you that your pet's theory of the universe goes against the Maxwell equation - then it is much worse for Maxwell's equations. If found to be contrary to observations - well, these experimentalists sometimes do certain things. But if your theory is found to be contrary to the second law of thermodynamics, I can not give you hope; there is nothing to it but to collapse in the deepest insults.
In the mid-19th century, Henry Dircks investigated the experimental history of continuous movement, wrote a very sharp attack on those who kept trying what he believed was impossible:
"There is something sad, degrading, and almost insane in pursuing past visionary schemes with determination, in the path of learning that has been investigated by the superior mind, and by which such adventurers have absolutely no idea." The history of Perpetual Motion is history of the stupidity of people who are half-learning, or really stupid. "
Technique
Some general ideas repeated over and over again in immutable motion machine design. Many ideas continue to emerge today declared in early 1670 by John Wilkins, Bishop Chester and a Royal Society official. He outlines three potential sources of power for perpetual motion machines, "Chymical [ sic ] Extraction", "Magnetical Virtues" and "The Natural Affection of Gravity".
The seemingly mysterious magnetic ability to influence movement at long distances without a clear source of energy has long appealed to inventors. One of the earliest examples of magnetic motors was proposed by Wilkins and has been widely copied because: it consists of a rise with a magnet at the top, which pulls a metal ball over a hill. Near the magnet is a small hole that should allow the ball to fall under the road and back down, where the flap allows it to back up again. The device can not work. Faced with this problem, a more modern version typically uses a series of ramps and magnets, positioned so that the ball must be passed from one magnet to another while moving. The problem remains the same.
Gravity also acts in the distance, without a clear source of energy, but to gain energy from the gravitational field (for example, by dropping heavy objects, generating kinetic energy when falling) one has to put energy in (for example, by lifting the object up), and partially energy is always lost in the process. The typical gravitational application in the perpetual motion machine is the 12th-century Bhaskara wheel, whose main idea is a recurring theme, often called an overly balanced wheel: the moving weight is attached to the wheel in such a way that it falls to a position farther from the center of the wheel for one half wheel round, and closer to the center for the other half. As the weight farther away from the center implements greater torque, it is expected that the wheel will spin for good. However, since the sides with weights further from the center have less weight than the other side, at that time, balanced torque and perpetual motion are not reached. The moving weight may be a hammer in a rotating arm, or a rolling ball, or mercury in a tube; the principle is the same.
Another theoretical machine involves a frictionless environment for movement. This involves the use of diamagnetic or electromagnetic levitation to float an object. This is done in a vacuum to remove friction and air friction from the shaft. The lifted object then freely rotates around its center of gravity uninterruptedly. However, this machine has no practical purpose because the rotated object can not do any work when the job requires a raised object to cause movement in another object, bringing friction into the problem. Furthermore, the perfect vacuum is an objective that can not be achieved because the container and the object itself will slowly evaporate, thereby lowering the vacuum.
To extract work from heat, resulting in a second type immortal motion machine, the most common approach (dating back at least to the Maxwell demon) is unidirectionality . Only molecules that move fast enough and in the right direction are allowed through the ghost trap door. In the Brownian ratchet, troops that tend to rotate the ratchet in one way can do it while the force in the other direction is not. A diode in a hot bath allows through the current in one direction and not the other. This scheme usually fails in two ways: both preserving the energy cost of unidirectionality (requiring the Maxwell demon to do more thermodynamic work to measure the molecular velocity than the amount of energy gained by the temperature difference caused) or unidirectionality is an illusion and sometimes a massive breach of redeeming it often minor offenses (Brownian forces will be subject to the Brownian internal forces and therefore will sometimes change direction).
Floating is another often misunderstood phenomenon. Some propose a perpetual motion machine losing the fact that to push the volume of air into the liquid takes the same job to raise the corresponding fluid volume against gravity. This type of machine may involve two chambers with a piston, and a mechanism for pressing air out of the upper chamber to the bottom, which then becomes buoyant and floats upward. The pressing mechanism in this design will not be able to do enough work to move the air down, or it will leave no excess work available for extracting.
Patent
Proposals for such non-operating machines became so prevalent that the United States Patent and Trademark Office (USPTO) has made an official policy to refuse to grant patents for perpetual motion machines without a working model. The USPTO Manual of Patent Examining Practice states:
With the exception of cases involving perpetual motion, the model is not usually required by the Office to indicate the operability of the device. If the operation of a device is questioned, the applicant must assign it to satisfy testers, but he can choose his own way.
And, furthermore, that:
Rejection [of patent application] on the basis of lack of utility includes a more specific reason of non-operation, which involves continuous motion. Rejection below 35 U.S.C. 101 due to lack of utility should not be based on the reason that the invention is reckless, fraudulent or contrary to public policy.
Filing a patent application is a clerical task, and the USPTO will not refuse filing for perpetual motion machines; An application will be filed and most likely rejected by a patent examiner, after he or she performs a formal examination. Even if a patent is granted, it does not mean that the invention actually works, it just means that the tester believes it is working, or can not figure out why it did not work.
USPTO stores a collection of Gimmicks Perpetual Motion.
The Royal Patent Office has a special practice of perpetual motion; Section 4.05 of the UKPO Patent Practice Manual states:
Processes or articles that allegedly operate in a way that clearly contradicts established physical laws, such as perpetual motion machines, are considered to have no industrial applications.
Examples of decisions by the British Patent Office to refuse patent applications for perpetual motion machines include:
- The decision of BL O/044/06, application of John Frederick Willmott no. 0502841
- The decision of BL O/150/06, application Ezra Shimshi no. 0417271
The European Patent Classification (ECLA) has classes including patent applications on perpetual motion systems: ECLA class "F03B17/04: Suspected perpetua mobilia..." and "F03B17/00B: [... machine or machine] (with closed loop circulation or the like:... Installation where the liquid circulates in a closed loop; Alleged mobilia or something like this... ".
Apparently perpetual motion machine
Since the "eternal movement" exists only in isolated systems, and the actual isolated system does not exist, there is no real "perpetual motion" device. However, there are concepts and technical concepts that propose "perpetual motion", but on closer analysis it is revealed that they actually "consume" some kind of natural resources or latent energy, such as phase changes of water or other liquids or natural small temperature gradients, or can not maintain unlimited operation. In general, extracting work from this device is not possible.
Consume resource
Some examples of such devices include:
- The function of drinking bird toys uses gradients and evaporation of small environmental temperatures. It runs until all the water evaporates.
- The capillary action-based water pump function uses a small environmental temperature gradient and a vapor pressure difference. With the "Capillary Bowl", it is thought that capillary action will keep the water flowing in the tube, but because the cohesive force that pulls the liquid up the tube in the first place holds the droplets from releasing into the bowl, the flow is not lasting.
- The Crookes radiometer consists of a partial vacuum glass container with light-weighted propellers driven by a temperature gradient (induced by light).
- Any device that takes a little energy from the surrounding natural electromagnetic radiation, such as a solar powered motor.
- Any device powered by air pressure changes, such as a few hours (Cox watch, Beverly Clock). The movement dissipates energy from the moving air which in turn gains its energy from action.
- The Atmos clock uses a change in the vapor pressure of ethyl chloride with temperature to rotate the spring springs.
- A device supported by radioactive decay of an isotope with a relatively long half-life; such devices can operate sensibly for hundreds or thousands of years.
- The Oxford Electric Bell and Karpen Pile are driven by dry stacked batteries.
Low friction
- In the flywheel energy storage, "modern style wheels can have a loadless, no-load time that can be measured in years".
- After spinning, objects in a vacuum - stars, black holes, planets, moons, spin-stable satellites, etc. - wastes energy very slowly, lets them spin for a long time. Tides on Earth scatter gravity energy from the Moon/Earth system at an average rate of about 3.75 terawatts.
- In certain quantum mechanical systems (such as superfluidity and superconductivity), very low friction movements are possible. However, the motion stops when the system reaches an equilibrium state (eg All liquid helium arrives at the same level.) Similarly, the visible-reverse entropy-like effect of superfluid climbing the container wall operates by ordinary capillary action.
Experiment thought
In some cases, thought experiments (or gedanken ) seem to indicate that perpetual motion is possible through accepted and understood physical processes. However, in all cases, defects have been discovered when all relevant physics are considered. Examples include:
- Maxwell's demon: It was originally proposed to show that the Second Law of Thermodynamics is applied in a statistical sense only, by postulating "demons" who can choose energetic molecules and extract their energy. Further analysis (and experiment) has shown there is no way to physically implement such a system that does not result in an overall increase in entropy.
- Brownian ratchet: In this thought experiment, one imagines a paddle wheel connected to a ratchet. Brownian motion will cause the surrounding gas molecules to attack the oars, but the ratchet will only allow it to spin in one direction. Careful analysis shows that when a physical ratchet is considered on this molecular scale, Brownian motion will also affect the ratchet and cause it to fail randomly so there is no net gain. Thus, the device will not violate the Law of Thermodynamics.
- Vacuum energy and zero-point energy: To explain effects such as virtual particles and the Casimir effect, many quantum physics formulations include a background energy surrounding an empty space, known as vacuum or zero-point energy. The ability to utilize zero-point energy for useful work is considered pseudoscience by the scientific community at large. The inventors have proposed various methods for extracting useful work from zero point energy, but none were found feasible, no claims for zero-point energy extraction were ever validated by the scientific community, and there was no evidence that zero- Point energy could be used in violation conservation of energy.
See also
- Exceptional utility
- Pathological Sciences
- Pseudosains
- Johann Bessler
References
External links
- Perpetual motion in Curlie (based on DMOZ)
- The Functioning Tool Museum
- Vlatko Vedral's Long Discussion on Maxwell's Demon (PDF)
- "Perpetual Motion - Just Is not." Popular Mechanics , January 1954, p. 108-111.
- In Our Time: Perpetual Motion, a BBC discussion with Ruth Gregory, Frank Close and Steven Bramwell, hosted by Melvyn Bragg, the first broadcast of September 24, 2015.
Source of the article : Wikipedia
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