Echo
Clapping hands or snapping ones fingers whilst standing next to perpendicular sheets of corrugated iron (for example, in a fence) will produce a high-pitched echo with a rapidly falling pitch. This is due to a sequence of echoes from adjacent corrugations.
If sound is traveling at 344 m/s and the corrugated iron has a wavelength (pitch) of 3” or .0762 m this will produce an echo with a maximum wavelength of that order, which corresponds to a frequency of 4500 Hz or so (approximately the C above top A on a standard piano). The first part of the echo will have a much higher pitch because the sound impulses from iron nearly opposite the clapper will arrive almost simultaneously.
Read more about this topic: Corrugated Galvanised Iron
Famous quotes containing the word echo:
“True ease in writing comes from art, not chance,
As those move easiest who have learn’d to dance.
‘Tis not enough no harshness gives offence,
The sound must seem an echo to the sense:”
—Alexander Pope (1688–1744)
“To write is to make oneself the echo of what cannot cease speaking—and since it cannot, in order to become its echo I have, in a way, to silence it. I bring to this incessant speech the decisiveness, the authority of my own silence.”
—Maurice Blanchot (b. 1907)
“Grace! ‘tis a charming Sound,
Harmonious to my Ear!
Heav’n with the Echo shall resound,
And all the Earth shall hear.”
—Philip Doddridge (1702–1751)