| What did light have to do with electricity or magnets? It was
Maxwell’s genius to see that light (which had always been
a mystery anyway) must be made of these waving electric and magnetic
fields. Not only that, but Maxwell could see that there must be
many other kinds of light — light invisible to our eyes and
unknown to science.
In 1887, German scientist Heinrich Hertz found one kind of invisible
light, called radio waves. Soon, Italian engineer Guglielmo Marconi
used those radio waves in a new way.
In 1901, a radio signal was generated at Poldhu, Cornwall, on the
west coast of England. It travelled 3400 km to St. John’s,
Newfoundland, where Marconi and his crew waited and listened. A
122-metre-tall antenna, held aloft by a kite, whipped about in high
winds. Despite the dreadful weather, Marconi heard the radio signal
— three dots, the Morse code symbol for “s”. With
this simple message, sent across an ocean on a wave of invisible
light, the radio era had begun.
So, where does the microwave fit in? Be patient, Grasshopper.
Until next time... |
Electric motors and generators. Where would we be without them?
Back in the 19th century, before English scientist Michael Faraday
found that wires and magnets had something called “a field”.
That discovery led to our high-tech modern lifestyle. So, what is
a field?
In 1879, a Scottish scientist named James Clerk Maxwell developed
a mathematical description of Faraday’s “fields”.
In his mathematics, Maxwell found that as electric and magnetic
fields changed, they travelled together through space as a single
wave, what we call today an electromagnetic wave. Maxwell’s
mathematics even told him how fast that wave moved.