Physics is the type of science that deals with the laws of nature. Thermodynamics is a field in physics that we will focus on today as well as the basic understanding of what perpetual motion machines are and the why and how they can’t exist.
Physics has a field in what is called “thermodynamics.” The field focuses on heat transfers between properties such as density, temperature, and pressure. Thermodynamics “focuses largely on how a heat transfer is related to various energy changes within a physical system undergoing a thermodynamic process,” usually guided by the laws of the field (Jones).
In basic concept, the thermodynamic process has special properties alongside it like: “Adiabatic process – a process with no heat transfer; Isochoric process – no change in volume in which case the system does no work; Isobaric process – a process with no change in pressure; Isothermal process – no change in temperature” (Jones). These have to do with changes in pressure, internal energy like temperature, and volume.
There are four laws that help guide these processes: “Zeroeth – Two systems each in thermal equilibrium with a third system are in thermal equilibrium to each other; First – The change in the energy of a system is the amount of energy added to the system minus the enerfy spent doing work; Second – It is impossible for a process to have as its sole result the transfer of heat from a cooler body to a hotter one. Third – It is impossible to reduce any system to absolute zero in a finite series of operation. This means that a perfectly efficient heat engine cannot be created” (Jones). These are important to know for understanding why perpetual motion machins can’t exist.
What does this have to do with perpetual motion machines though? And what are these machines exactly? It has several definitions according to “The Museum of Unworkable Devices” website. The three that it gives us are: “Any device that continues its motion forever, without any speed reduction (The literal interpretation); Any device whose operation would violate established laws of physics, or would depends upon purely speculative laws unknown to physics; A machine that perpetually puts out more energy than it takes in” (Simanek). Machines that can move and work without any means of energy even though it can put out energy. An interesting concept that would change the world. Unfortunately, this doesn’t exist, it is only hypothetical due to thermodynamics. And that is where these two topics come together.
Many scientists say that these machines can’t work due to the laws of thermodynamics; that they can’t work because they violate them. “Perpetual motion machines of the first kind violate the first law of thermodynamics. They produce more energy output than input, that is, they have an efficiency greater than one; [PMM] of the second kind violate the second law of thermodynamics. They would involve zero or negative changes of entropy” (Simanek). Entropy “…is a quantitative measurement of the disorder in a system” (Jones).
If these were to work and exist, they would go against physics itself because of how they make energy and transfer heat. We will always try to make them work, but it really would not make sense due to how they would make energy. Having no energy input, but having them make an output of energy greater than one, is realistically and scientifically impossible.
However, they continue to push the limits and try to create something that they know can’t work. Why? “…inventors do not believe their machines violate the laws of physics” as well as not being able to grasp logical unity which is physics greatest strength (Szalay).
In conclusion, understanding thermodynamics is not complete without knowing about perpetual motion machines. They rely on each other to understand one another. Through the process of trying to make a PMM, to knowing that it just can’t exist is why physics is around. An interesting topic to talk about because if this were possible, it would change the world because we use energy nonstop. If we could find a way to make an energy machine without using energy, well that is amazing.
References
Jones, A. Z. (2017, July 10). Learn the Key Elements of Thermodynamics: The Physics of Heat. Retrieved July 10, 2017, from https://www.thoughtco.com/thermodynamics-overview-2699427
Simanek, D. E. (2006, January). The Museum of Unworkable Devices. Retrieved July 10, 2017, from https://www.lhup.edu/~dsimanek/museum/unwork.htm
Szalay, J. (2016, August 30). Perpetual Motion Machines: Working Against Physical Laws. Retrieved July 10, 2017, from https://www.livescience.com/55944-perpetual-motion-machines.html
