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Stumper #43.






How Good Is Your Science KQ?
[i.e. your Knowledge Quotient]

Who Invented Radio?

In conversation some years ago my father reminisced about his 1920's teenage memory of making a 'crystal radio.' "You had to tickle it, you know," he said, "to find the sensitive spot." The crystal he used was galena and the 'tickle' was accomplished with a piece of wire just touching the crystal's surface. His simple radio contraption required, of course, the existence of broadcast radio waves to listen to.

microphone By the time my father was experimenting with his crystal radio, discoveries and inventions over the previous forty years had contributed to the development of the wireless method of transmitting signals. In the 1860s, James Clerk Maxwell predicted the existence of radio waves, and in 1886 Heinrich Rudolph Hertz had actually demonstrated that rapid variations of electric current could be projected into space in the form of radio waves similar to those of light and heat.

As early as 1892, a basic design for the use of radio waves to carry a signal had been created by Nikola Tesla and in 1895 Guglielmo Marconi sent and received his first radio signal in Morse Code. Marconi is often cited as the inventor of radio; however, in 1943 the U.S. Supreme Court ruled that Marconi's patents were invalid due to Tesla's previous descriptions.

radio tower In March 1897, Alexander Popov equipped a land station at Kronstadt and a Russian navy cruiser with a wireless communications apparatus for ship-to-shore Morse code communications. By the turn of the century Morse code signals were being transmitted by wireless over great distances.

The first wireless transmission of voice and music happened in December 1906 when Reginald Fessenden transmitted a recording of Handel's "Largo" on an Ediphone, played "Oh Holy Night" on the violin, and read from the Bible before wishing wireless operators of several ships in the Atlantic a Merry Christmas.

So, who really invented radio? The answer has to be that several men discovered radio waves, others invented both simple and sophisticated ways of using them, and yet others made 'radio' into a "household utility."

The Stumper Questions:

1. What name is given to the invention that uses the reflection or echo of radio waves to detect objects or measure distances?

2. Which of the following has usefully reflected radio waves from transmitters on Earth back to Earth: a) the ionosphere, b) the Moon, c) man-made satellites, d) Mars

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