Perpetual Motion:
Is It Possible?
Siddharth Veerapaneni
Embedded Files
The magic wheel of mediaeval Bavaria was a wagon wheel that convinced the population of the Dark ages of the powers of magic by continuing to spin for an incredibly long time after being started. In reality, this ‘magic’ was simply several lodestones attached to the wheel’s outside rim with one stationary magnet attached to the base. The Bavarian magic wheel was one of the very first of many attempts at building a perpetual motion machine.
A system that can indefinitely do work without the input of any energy is known as a perpetual motion machine. Essentially, if such a system was created today, it would continue to move until the ‘Big Freeze’, which is the theoretical end of everything where the universe will have expanded to a state with zero thermodynamic free energy; every particle in the cosmos will be at absolute zero. Needless to say, this is a very, very distant event.
While various designs have come and gone over the centuries, such a machine remains hypothetical, and to make matters worse, we can fundamentally disprove its existence using the First and Second Laws of Thermodynamics. In order for a perpetual motion machine to be of any real use, we must be able to extract work from it and use it to power machines. However, this is not possible according to the First Law of Thermodynamics, which can written in its equation form as ∆U=Q-W, where ∆U is the change in internal energy, Q is heat transfer to the system from its surroundings and -W is the work done by the system on its surroundings. A hypothetical perpetual machine would have a Q value of 0 and an increasingly positive value of W, resulting in an increasingly negative ∆U, which represents an infinite extraction of internal energy. Sadly, this does not obey the law of conservation of energy, and so is impossible.
However, another type of perpetual motion machine exists where an input of energy is conserved perfectly and indefinitely, with no energy being transferred to the surroundings as heat or sound. While no work can be extracted from the energy, all of the energy inputted initially is stored. The greatest obstacle to this type of perpetual motion is the loss of kinetic energy due to friction between particles in contact. Over time, the machine loses all its energy and eventually comes to a stop. An obvious solution is to make your system entirely frictionless, which is easier said than done. However, systems with zero friction do exist. Superfluidity is the property of a liquid flowing with zero-resistance, and thus without loss of kinetic energy. This property ‘phenomenon’ was discovered in 1938 in helium-4 at below 2.17 K (near absolute zero.) Although extensive research into helium’s superfluidity has been carried out for decades, its atomic mechanism is still not fully understood. It is theorised to be a new quantum state of matter in which particles can “travel through an energy barrier rather than going over it”: a process termed as ‘quantum tunnelling.’ Superfluidity can also be observed in an electrically charged system as superconductivity- another property ‘phenomenon’ where current can flow in a superconducting ring forever.
While such a machine providing infinite work is impossible, future research into perpetual motion in superfluidity and superconductivity could prove extremely beneficial. We are entering an age where efficiency in power and energy has never been more important; perpetual motion may be the key to unlocking the answers.
Page updated
Report abuse