Perpetual motion machines (i.e., devices that, once set in motion, would continue in motion forever, with no additional energy required) – are they possible? Well, not according to the first and second laws of thermodynamics.
First law of thermodynamics:
When energy passes, as work, as heat, or with matter, into or out from a system, its internal energy changes in accord with the law of conservation of energy.
Second law of thermodynamics:
In a natural thermodynamic process, the sum of the entropies of the interacting thermodynamic systems increases.
Perpetual Motion Machines
Even though the first two laws of thermodynamics tell us that perpetual motion machines are impossible, the idea of making one has fascinated both inventors and the general public for hundreds of years. The promise of a virtually free and limitless source of power has tempted many inventors to try to break, circumvent, or ignore the first two laws of thermodynamics.
Here are a couple of videos showing working models of the perpetual motion machines that have been proposed over the years.
These videos could serve as a springboard for discussions about inventors and inventions and the history of scientific endeavors. They would be suitable for teachers of middle to senior secondary students in Science.