Hertz's Radio Wave Experiment: A Comprehensive Study | Resources and References

[MPonte]

I am from Portugal and from the school books I could not understand in all his dimension Hertz experiment in which he produced radio waves in laboratory. If you could refer some sites (I have searched a lot) it will be good but even better if you could send me some pages scanned from books concerning this topic.

Thank you.

 

[Astronuc]

http://www.acmi.net.au/AIC/HERTZ_BIO.html

In 1888, in a corner of his physics classroom at the Karlsruhe Polytechnic in Berlin, Hertz generated electric waves by means of the oscillatory discharge of a condenser through a loop provided with a spark gap, and then detecting them with a similar type of circuit. Hertz's condenser was a pair of metal rods, placed end to end with a small gap for a spark between them. When these rods were given charges of opposite signs, strong enough to spark, the current would oscillate back and forth across the gap and along the rods. With this oscillator, Hertz solved two problems: 1) timing Maxwell's waves (he had demonstrated, in the concrete, what Maxwell had only theorized: that the velocity of radio waves was equal to the velocity of light), and 2) how to make the electric and magnetic fields detach themselves from wires and go free as Maxwell's waves.

Hertz's students were impressed, and wondered what use might be made of this marvelous phenomenon. But Hertz thought his discoveries were no more practical than Maxwell's. "It's of no use whatsoever," he replied. "This is just an experiment that proves Maestro Maxwell was right -- we just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there."

http://www.webstationone.com/fecha/hertz.htm

http://chem.ch.huji.ac.il/~eugeniik/history/hertz.htm - schematic of experimental apparatus (about half-way down page)

http://www.sparkmuseum.com/HERTZ.HTM

http://people.deas.harvard.edu/~jones/cscie129/nu_lectures/lecture6/hertz/Hertz_exp.html - Heinrich Hertz's Wireless Experiment (1887)

http://www.pupman.com/hvlistarchives/2004/Apr/msg00003.html

 

[PPonte]

Thank you Astronuc. I already visited some, but others not. I just do not understand what are those big spheres for. Could you explain?

 

[Astronuc]

I believe the metal (conducting) spheres were used to store significant amounts of charge. The spherical surface is ideal because is avoids any sharp corners where there would be strong local gradients in the electric field. The principal has been used in Van de Graaff generators to store large charges which provide for large potential differences.

 

[PPonte]

Thank you for the explication.