- The famous drinking bird toy is an example of a heat engine that is incorrectly considered to be a perpetual motion machine.
- Perpetual motion machine is not possible because it goes against the first and the second law of thermodynamics.
- One of the most famous examples of an apparent perpetual motion machine is the Beverly Clock in New Zeland.
Have you ever had a chance to play with a drinking bird toy? These toys convert heat to mechanical energy and once you set them in motion, they mimic the motion of drinking water. This drinking bird toy is sometimes called the perpetual motion machine, but this is not true, as that would go against the laws of thermodynamics.
The bird will continue to move as long as there is a source of water to produce an energy change. A perpetual motion machine, however, is a machine that can do work without an energy source, and such perpetual motion is supposed to work indefinitely. Is this possible?
What Is a Perpetual Motion Machine?
"Oh ye seekers after perpetual motion, how many vain chimeras have you pursued? Go and take your place with the alchemists."- Leonardo da Vinci
No, a perpetual motion machine cannot exist, and that is why a perpetual motion machine is a hypothetical machine. Such a machine would effectively violate the first and the second law of thermodynamics. The first law states that energy can only be transformed, but not created or destroyed, and the perpetual machine would do just that- it would produce work without energy. The second law states that some energy is always lost when the heat is converted into work, and that would mean that the perpetual motion machine would have energy that was never lost.
No example of perpetual motion is happening above the atomic level in our nature. This hypothetical machine has been a human desire ever since we created simple machines (it dates back to the Middle Ages), but the machine that would work on its own and work indefinitely has never been invented and is not possible.
Many people have tried, and even continue to attempt to construct such a machine, however, most modern inventors have a goal of constructing a machine that produces more work than the amount of the energy it got. They do not want perpetual motion per se, they want over-unity performance.
Examples Of Apparent Perpetual Motion Machines
Some concepts propose perpetual motion machines, but in reality, these machines will always need to have some resources or energy to operate indefinitely. One such example is the Beverly Clock, located in Dunedin, New Zealand. It was invented by Arthur Beverly in the 1860s and has never been wound, and it is still working due to the pressure of the atmosphere and temperature changes.
The clock was stopped on a few occasions because of mechanical issues. It is often considered to be the closest experiment that resembles a perpetual motion machine. Cox's timepiece is one also one such example, developed in the 1760s. It was said by James Cox that it was a true perpetual motion but the device is also dependant on changes in atmospheric pressure.