What is Perpetual Motion?
In the world of commerce, buying or selling usually involves paying a fee to an agent or stockbroker to cover the cost of the transaction. Nature, too, charges a commission on its energy transactions and, as a result, it is not possible to transfer energy completely from one useful form to another. When gasoline is burned in a motor car engine, chemical energy stored in the gasoline is changed into the energy of motion and heat, but the useful energy of motion is far less than is theoretically available in the gasoline.
Furthermore, if the car moves along the road, nature continues to demand a fee by absorbing some of this energy as frictional energy in the moving parts of the machine, and also in work done against air resistance. Even here, however, the energy is not lost but converted into other unwanted forms.
Engineers have tried to reduce nature's fee by better lubrication of the bearings, streamlining the car's body and re-designing the engine, but the gasoline engine is still only about twenty per cent efficient. Nature gets an eighty per cent commission. Some inventors have given much time and effort to the creation of machines which they hoped would be one hundred per cent efficient. Such perpetual motion machines, once started, would continue to operate without any further assistance. None has ever worked and there are good reasons to believe that none ever will.
The search for more efficient engines inspired scientists to delve deeper into the theory of energy and they found that although one hundred percent efficient engines were impossible, efficiency could be increased by raising the working temperature of the engine.
This led to a search for materials which could stand up to very high temperatures and still maintain their physical properties, such as strength and resistance to wear. Metallurgy, the study of metals, was and still is the highly important branch of science responsible for the development of new alloys which can be used at high temperatures in spacecraft, atomic power stations and jet engines.