Man's physical universe

xanabras

UNIT VII

THE APPLICATIONS OF MAGNETISM AND ELEC-

TRICITY HAVE GREATLY MODIFIED THE

ACTIVITIES OF MANKIND

INTRODUCTION TO UNIT VII

No better illustration of the impact of Science on the activities of

mankind can be found than magnetism and electricity. Suppose that

all

the sources of electric power were suddenly and permanently cut

off; the results would be similar to those experienced in a large city in

one of those very rare occurrences when the power is shut ofi for a few

hours due to damage produced by an electrical storm. Streetcars cease

to run, motion-picture theaters are darkened, stores and ofifices must

close, elevators cannot operate, water cannot be pumped through the

city's distribution system, and, in general, man would find himself

reduced to the life of a backwoods farm, except that he would not be

equipped with candles or kerosene lamps and would not have his own

private well or spring to furnish water.

Modern civilization is built around electricity. Without electricity

modern factories could not run; the radio, the telephone, and the telegraph

could not exist. Many modern homes would not be prepared for

heating, refrigeration, lighting, cooking, washing, ironing, cleaning, or

ventilation if the electricity were to be cut off. Even motorcars and

airplanes depend on electrical ignition systems.

In this Unit we shall study the development of knowledge concerning

electricity and magnetism and show how it has been applied in the

service of mankind.

The revolution in living produced by the application

of electricity has, for the most part, taken place during the lifetime

of our parents and has become widespread within the lifetime of

most of the freshmen in college today. This can be appreciated best

by reference to the fact that the wholesale sale of energy increased from

3,254,000,000 kilowatt-hours in 1912 to 44,326,000,000 kilowatt-hours

in 1929, or 1360 per cent. Since 1929 the consumption of electric

energy has been steadily increasing.

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