Physics-Conversion of Energy

Physics-Conversion of Energy

Beginning in the year 1840, James Joule performed a long series of experiments to study the conversion of mechanical energy to heat. In one experiment he used a barrel to heat water by rotating a paddle wheel inside the barrel. He measured the work done in turning the wheel and the heat produced in the water, and found that a given amount of work always produced the same amount of heat. Later experiments showed that heat and mechanical energy are always converted back forth in precisely the same ratio. We now know that the same rule is true for all forms of energy. In everyday terms, energy is never lost: When it disappears in one from, it always shows up in an equal amount in another form. This principle- known as the law of conservation of energy- is one of the fundamental laws of classical physics and is a very cornerstone of modern science and technology.

When it comes to the subject of energy, we should understand why a nation like the United States cannot solve its energy problems by operating automobiles on electricity instead of gasoline. It should be clear by now that electrical energy is no easier to come by than the chemical energy in gasoline. Neglecting engine efficiency for the moment, it takes the same amount of energy to move an automobile a given distance regardless of the initial source of that energy. If all our autos ran on electricity, that energy could be supplied only by burning additional fossil or nuclear fuel at our electricity generating plants. It is true, of course, that electric motors are more efficient than gasoline engines. But this advantage might well be offset by the weight of the batteries to be carried about.