Man's physical universe

xanabras

294 FORMS OF ENERGY

for nothing." It is the law of conservation of energy. A more technical

statement of the first law of thermodynamics is that in the transformation

of work into other forms of energy and in all energy transformations

there is no gain or loss of energy.

No scientist would ever consider any scheme that involved "getting

something for nothing." Many inventors, unaware of this fundamental

principle, have attempted to devise perpetual-motion machines;

and the average person would not be greatly surprised to see one in

operation, although he would be attracted by the novelty of it.

perpetual-motion machine is a machine that would do work indefinitely

without the expenditure of energy. The first law is based in part

on man's consistent failure to construct a perpetual-motion machine.

A machine that would continue to move indefinitely without doing

work is impossible, because a perfectly frictionless machine cannot

be built and friction always decreases the mechanical energy with

the formation of heat.

The Second Law of Thermodynamics. The second law of thermodynamics,

stated non-technically, is: "Everything in the universe tends

to run down." A clock always runs down. Water runs downhill

and never up, unless an outside force is brought into play. A bullet

gradually loses speed and never gains speed after it has been fired.

A human being grows old but never grows younger physically. People

who realize the significance of this law would seek help from sources

of power greater than they possess. They would seek to associate

with people of greater ability and development if they really wanted

to grow themselves. Gilbert N. Lewis expressed the statistical nature

of the second law of thermodynamics when he stated, "Stripped of

its finery we find that the second law states that if a pack of cards

is thrown into a shufifling machine the chances are that it will become

shuffled." The thought that Mr. Lewis thus expressed is that any

system left to itself approaches a definite state of equilibrium. This

law implies that the universe is running down and will eventually

come to a dead stop, but some people believe that additional knowledge

will show that the universe is not running down. At present there is

nothing that we can do about this problem; and it is unimportant

anyhow, so we will not pursue it further.

Technically, the second law of thermodynamics states that heat

energy tenuis to flow from a higher to a lower temperature and will not

flow by itself from a lower to a higher temperature. In other words,

heat, just as water, does not flow uphill.

The consequences of thermodynamical reasoning have not only

enabled the engineer to design more efficient heat engines, but they

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