On a German stamp celebrating one hundred years of radio transmission
Early in the 19th century, Michael Faraday, an English physicist, demonstrated that an electrical current could produce a magnetic field.
In 1864, James Clerk Maxwell, a professor of experimental physics at Cambridge, proved mathematically that any electrical disturbance, that generates an electromagnetic field, could produce an effect at a considerable distance from the point at which it occurred and predicted that electromagnetic energy could travel outward from a source as waves moving at the speed of light.
In 1888 Heinrich Hertz demonstrated that Maxwell’s prediction was true for transmission over a short distance.
In 1901 the Italian physicist, Guglielmo Marconi, perfected a radio system that transmitted Morse code over the Atlantic Ocean.
In 1906 the American physicist Lee De Forest invented the vacuum tube which amplified radio signals that were received by antenna, thus much weaker signal could be transmitted over longer distance. The vacuum tube was also used to generate radio waves and soon become the main component of radio transmitter.
After World War II more advancements were made: The replacement of the vacuum tube by the transistor and of wires by printed circuits drastically reduced the power that radio equipment needed to operate enabling radio components miniaturization and more reliability.
During the years claims were made that as a matter of fact not Marconi invented radio but Oliver Lodge, Alexander (Aleksandr) Popov or Nikola Tesla , had sent wireless messages before Marconi got his patent.
It does not really matter. What Marconi undoubtedly did invent was an entirely new science-based industry. In his hands an obscure and, to most people, unintelligible branch of physics became a consumer product like no other. We are used to being told that some new technology will change the world. Marconi's is one of the few that did.
For his scientific contribution Marconi was awarded the Nobel Prize in physics for the year 1909.
As a rule: experiments with electricity should be performed under the supervision of teachers or adults familiar with electricity safety procedures. Especially, take in account that experiments with induction coils and capacitors can produce high voltage shocks.
Marconi's experiment – creating, sending and detecting radio waves – is relatively simple, not beyond the abilities of middle school students. In order to begin, read carefully the resources provided by this site and ensure that you understand the basic principals. Brows further the web and consult your local library, your teacher and other knowledgeable adults and experts.
Books
Bray, J. The Communications Miracle. New York: Plenum, 1995
Bussey, G. Marconi's Atlantic Leap. Coventry: Marconi Communications, 2001
Garratt, G. R. M. The Early History of Radio from Faraday to Marconi. London, IEE, 1993
Marconi, D. My Father, Marconi. Toronto: Guernica Editions Inc., 2nd edn, 1996
Marconi's Experiments Links:
Guglielmo Marconi: Radio Star - physicsweb
Marconi's Patent: 1900 - Sparkmuseum
Article from "Experimental Science, G.M. Hopkins, 1902" - Frederick Collins
Did Marconi Receive Transatlantic Radio Signals? - Henry M. Bradford
A Look at Some of Marconi's Technology - R. Victor Jones
More Radio Science Fair Projects:
Electronics Science Fair Projects and Circuits
Invention of Radio History Links:
Who Invented Radio?
A World of Wireless
Guglielmo Marconi: Radio Star - physicsweb
Tesla: Master of Lightning - PBS
Nikola Tesla Pages
Alexander Popov: Russia's Radio Pioneer - James P. Rybak
