An experiment from 1632 by Galileo ...the first ever 'Sound Recording'?

In his book 'Dialogue Concerning the Two Chief World Systems' (1632), Galileo wrote: "As I was scraping a brass plate with a sharp iron chisel in order to remove some spots from it and was running the chisel rather rapidly over it, I once or twice, during many strokes, heard the plate emit a rather strong and clear whistling sound: on looking at the plate more carefully, I noticed a long row of fine streaks parallel and equidistant from one another. Scraping with the chisel over and over again, I noticed that any marks were left upon it; when scraping was not accompanied by this sibilant note there was not the least trace of such marks."

Category:

Science & Technology

Tags:

• First Sound Recording
• First Recording
• sound experiment

[MsHoly777]

i don't get it...............message me with the answer to this riddle please? THANKS

[ToneSpectra]

@MsHoly777 The visible lines on the brass plate are an impression left behind when the scraping of the chisel produces a definite pitch (note) rather than just friction noise. So, pitch is produced by periodic contact with the brass plate, whereas noise results from random contact with the plate. Similarly, if you run your thumbnail quickly along a fine toothcomb, the 'clicks' become recognisable as 'pitch'. The sound of the sea against rocks is random, which we hear as 'noise'. Thanks.

[ferociousgumby]

Looks like a zipper.