The excellent physics didactitian "Tibees" is exposing some physics students to a physics exam from 1888 here in this video, and in it you see they prove my point:
Physics students react to 1888 exam
Tibees | 13.XI.2019
One thing I note immediately is they suck at history of science.
- 1) Before Boltzmann and they didn't believe in atoms ... except they did (even if it wasn't Bohr's model)
- 2) "when was the first camera"
"The essential elements—a silver-plated surface sensitized by iodine vapor, developed by mercury vapor, and "fixed" with hot saturated salt water—were in place in 1837."
Sounds like some decades before 1888, wasn't it? If you read on, Talbot perfected calotype in 1840, also nearly five decades before the exam.
I can't find a useful diagram of a 19th C. camera online right now, but the reason would be, gaslight necessitated a longer exposure than was feasible for people without moving at all.
5:27 "Michael Faraday FRS (/ˈfærədeɪ, -di/; 22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry."
In St. Thomas Aquinas' day, iron was earth influenced by Mars and in the case of magnets, it was influenced by Venus as well.
So this is way after the time when "it's a bunch of metal that has those properties" ... if ever there was such a time.
And, no, Faraday dying in 1867 was not 20th C.
6:14 "they didn't even have one"
"The Bell System was the system of companies, led by the Bell Telephone Company and later by AT&T, which dominated the telephone services industry in North America from 1877 to 1984"
Yeah, right, 1877 was eleven years before this exam, so that was already a commercial or public service, not just experiments.
A membrane is set before someone's mouth, when he speaks it moves. A magnet is attached to it, affecting induction and therefore strength of electric current, the electric current is transmitted to the other phone where an electromagnet pulls and repels a magnet in another membrane, just like in a loudspeaker, except the receiving end membrane being held to the ear is much smaller than a loudspeaker. As the electric current changes intensity, the membrane vibrates and those vibrations reconstitute the sound to the air and to the ear.