h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Sorry. Nothing to do with Thomas Alva this one.



GT

Other Germans to do with Sound Vibration, electrickery....


Helmholtz - him of Helmholtz coil - which I cannot remember what it was but do remember something about from Physics - something to do with inductance?


Braun - already mentioned...

Van der Graff - him of the generator...

Expect a Klaxon for at least one of them...

Herman von Helmholtz


A membrane attatched to a Helmholtz coil is the basis of a loadspeaker!!!


+3!!


GT

Aha... Memories - of the things I used to know... Many misty coloured memories....

OK is there anything else we need to know now?

Will read backlog, and summise....

This is one of the longest QIs I have hosted!

Please be patient, I will answer shortly!


GT

GF - any chance of scoring this 'un?

I have it as...

Taff - Photocopier -5, Computer..... -5, Projector -5, Edison -5, Fax +1, Telephone +3, Bell +3, Telegraph +1, Electromagnet +3, Loudspeaker +1, Microphone +3, speech +1, Hearing Aid +6, Teacher to Deaf +3, Marconi -5, Kepler -5 = -6


Keith. - Scot. +3, Canada DGI +3, Electromagnet Microphone +3 = +9

Argon0 - Prior Claims DGI +3, Newton -5, Farraday +3, Electric into Sound +3, Helmholtz +3 = +7

Van-Smelter - Farraday and Electromagnetism DGI +1 = +1



Argon0

Oi GT scores please or I will go with Argons

Checked Argon's scores.....

Spot on!!


Go for it Bob!
(Thanx Argon!)



GT

No worries

bob has not picked up yet, so will run through myself, and give relevant answers and scores later.


GT

http://www.bbc.co.uk/dna/h2g2/brunel/F7180006?thread=7554410 Have a look here GT

Let us go with the story.

In 1874, Alexander Graham Bell, who was trying to help deaf-mutes to speak, saw a demonstration of a phonautograph, a device that had been devised by a Frenchman, Leon Scott. A thin stick was attatched to a membrane, and a bristle attatched to this. When the membrane is attatched to the end of a cone, to amplify the sound, and the bristle is set to touch a smoked glass plate, when you speak into the cone, the bristle makes a wavy line on the glass. Each different sound produces a different shape on the glass.

Using the work of Faraday,(Who discovered Electromagnetic Induction) Oerstead,(Who discovered how to make an Electromagnet, along with an Englishman called Sturgeon), and Herman Helmholz, who reversed the idea of the microphone to make sound- (Fluctuating magnetic field will cause a metal membrane to vibrate, causing sound)

Bell attatched the phonautograph to a membrane, which was attatched to a Faraday coil, through which an electromagnet was allowed to oscillate. The electromagnet was the result of work carried out by Oerstead and Sturgeon (Two men we missed!). This first unit was powered by battery, which also led to the 'speaker' side, which was developed by Herman Helmholz, who rightly guessed that a fluctuating magnetic field would cause a membrane to vibrate, causing sound.

Bell put all of it together to invent the telephone.


GT


(Now it is 0100 Hrs. Must be up tomorrow cos a)Missus gets paid, and b)Man coming to repair washer/drier that has gone titsup after only 18months


GT

Full scores therefore tomorrow!!

GT

Scores posted...

In short....


Taff -4

Keith Miller +6

Argon0 +10

Van Smelter +7



GT