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Radio. *Warning* Heavy Science Content Ahead. Baghdad battery – 250 BCE. Electricity was a heavy duty toy for decades, including Ben Franklin and his kite, people rubbing cat skins on glass or amber rods, spinning sulfur balls, and sparking everything and everyone in sight.

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Warning heavy science content ahead

*Warning*Heavy Science Content Ahead

Baghdad battery 250 bce

Baghdad battery – 250 BCE


  • Electricity was a heavy duty toy for decades, including Ben Franklin and his kite, people rubbing cat skins on glass or amber rods, spinning sulfur balls, and sparking everything and everyone in sight

Luigi galvani 1786

Luigi Galvani - 1786

  • Believed everything contained electricity

  • Looked for “animal magnetism”

  • Touched different metals to frogs’ legs which twitched

Alessandro volta 1796

Alessandro Volta - 1796

Alessandro volta 17961

Alessandro Volta - 1796

  • Volta took Galvani’s experiment and showed that it was the current produced by the different metals that caused the twitch

  • Built a pile of alternating sandwiches of zinc and copper in an acid and created electicity

Hans christian oersted 1820

Hans Christian Oersted - 1820

Oersted s experiment 1820

Oersted’s experiment - 1820

  • In a lecture in Copenhagen he performed an experiment to demonstrate there was no connection between electricity and magnetism by showing that an electric current passing through a wire wouldn’t affect a nearby compass needle


  • Imagine his surprise when the needle swung the moment he turned on the current

  • He demonstrated that electricity created a magnetic field

William sturgeon 1825

William Sturgeon - 1825

  • Created the first electromagnet by wrapping wire around a soft iron bar and sending a current through the wire

  • Electricity can create magnetism

Michael faraday 1826

Michael Faraday - 1826

  • Reversed Sturgeon’s experiment

  • Showed that magnetism could create an electric current

Samuel f b morse 1838

Samuel F. B. Morse - 1838


  • Used a an on-off switch – the telegraph key – to turn an electric current on and off, sending pulses of current through a wire to an electromagnet that would click in time to the pulses

Johannes mueller 1840

Johannes Mueller - 1840


  • Examined physical sensations

    • Can you feel colors

    • Can you hear shapes

    • Can you smell sounds

  • Discovered that each sense detects different things

  • We think this is obvious, but no one had proven it before. Remember “common sense”?

Herman hemholtz 1857

Herman Hemholtz - 1857


  • Meuller’s pupil

  • Investigated hearing

  • Noticed sound produced vibrations


  • Did the vibrations operate at different frequencies?

    • They did

    • Thus, sound traveled at different frequencies

  • Used an electromagnet to attract the arms of a tuning fork, causing it to vibrate and produce sound

Leon scott de martinville phonautograph 1857

Leon Scott de Martinville - phonautograph - 1857

  • Attached a bristle to a membrane at the end of a cone, set the bristle to touch a piece of smoked glass

  • Spoke into the cone

  • membrane vibrated to the sound and the bristle etched a wavy line onto the smoked glass

The telephone 1876

The Telephone - 1876

  • Scott’s membrane, Faraday’s electromagnet, Oersted’s and Sturgeon’s electromagnet, Morse’s wire and electrical current, Heimholtz’s vibration, Scott’s membrane

Bell and gray

Bell and Gray

Samuel morse

Samuel Morse

Heinrich hertz 1886

Heinrich Hertz - 1886


  • Hemholtz’s pupil

  • Investigated whether electricity traveled in frequencies the way sound did

Spark gap generator

Spark gap generator

Hertz spark gap experiment

Hertz’ spark gap experiment


Demonstrated that electricity traveled through air at specific frequencies, just like it did through wires

Guglielmo marconi 1894

Guglielmo Marconi - 1894

Marconi radio

Marconi radio

Morse key

Morse key

Marconi and his radio

Marconi and his radio

Nikola tesla

Nikola Tesla

Tesla coil 1891

Tesla coil - 1891

  • Developed the first amplifier coil, the Tesla coil

  • Raised the voltage of an electrical current high enough to allow the air to conduct the current

  • Key to wireless transmission of radio waves

Reginald fessenden

Reginald Fessenden


  • Felt that the variation in electrical amplitude created by a voice, just like on a telephone, could be carried by electrical wave of a radio signal

  • Did the first voice broadcast in 1900

    • Short range

    • Poor quality

  • Needed far more power

Ernst alexanderson

Ernst Alexanderson


  • Developed the Alexanderson Alternator, a machine capable of generating the power, up to 100,000 hertz, that Fessenden needed to piggyback voice onto radio waves

  • In Dec. 1906, Fessenden did the first good voice and music broadcast, going hundreds of miles

    • Poetry and a Bible reading

    • A woman singing opera

    • A violin playing a Christmas carol

Lee de forest

Lee de Forest


  • The audion tube is actually a Fleming valve (British term for tube) invented in England

  • de Forest simply added the bent wire

De forest s audion tube 1904

De Forest’s audion tube - 1904


  • Audion tube amplified the radio signal the way the Alexanderson generator increased the electrical power

  • de Forest didn’t know how the audion worked

  • Another man did

Edwin howard armstrong

Edwin Howard Armstrong


  • Investigated the audion tube, figured out how it worked, and improved it

  • Developed “regeneration”

    • The signal was fed back into the tube over and over again, up to 20,000 times a second

    • Vastly increased the power of the tube to output the signal – it was an amplifier

    • Raise the level enough and the tube becomes a transmitter

    • Armstrong invented the ability to broadcast sound


  • It combined high frequency waves with low frequency waves, then fed them back into the system to amplify the signal and increase its sensitivity

  • Resulted in the creation of the home, and the portable, radio

Armstrong s superheterodyne

Armstrong’s superheterodyne

  • Armstrong’s next invention was the superheterodyne

Crystal radio

Crystal Radio

David sarnoff

David Sarnoff


  • Enamored of radio

  • Saw the possibilities

  • Wrote the “Radio Music Box Memo” that outlined the commercial possibilities of radio

Rca radio corporation of america

RCA (Radio Corporation of America)

  • After World War I

  • Four companies merged their patents to create RCA

    • American Marconi

    • General Electric

    • American Telephone & Telegraph

    • Westinghouse

  • Sarnoff named as commercial manager


  • Used Armstrong’s inventions, building superheterodyne radios to build RCA, the Radio Corporation of America, into one of the biggest companies in the world

Radio stations soon opened all over the u s

Radio stations soon opened all over the U.S.

Including KWSC (now KWSU) in 1922, one of the first radio stations in the country

Https skylight wsu edu student

Examples of programming







Variety shows

Soap operas

Pretty much everything we get on TV today

Examples of programming

Fibber mcgee and molly

Fibber McGee and Molly

Burns and allen

Burns and Allen

Fred allen

Fred Allen

Abbott and costello

Abbott and Costello

Orson welles 1938

Orson Welles - 1938

Hindenburg disaster 1937

Hindenburg disaster - 1937

Edward r murrow

Edward R. Murrow

The advent of television

The Advent of Television


  • It was assumed that radio would be dead

    • Audiences would watch TV instead of listening to the radio

    • TV took over so many of the radio programs

      • Soap operas

      • Dramas

      • Sitcoms

      • Sports

      • news

Radio had a great advantage over tv portability

Radio had a great advantage over TV –Portability

Take it anywhere

Take it anywhere

Even in the car

Even in the car

New kinds of programming

New kinds of programming

  • Music

    • Top 40

    • Country

    • Rock

    • Easy listening

    • Golden oldies

  • Talk shows

Howard stern

Howard Stern

On the right rush limbaugh michael savage glenn beck

On the RightRush Limbaugh Michael Savage Glenn Beck

On the left ed schultz stephanie miller

On the LeftEd Schultz Stephanie Miller

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