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:
“If I had not come to America, where I felt free to formulate tentatively insights at which I had empathically arrived, I would have accomplished very little. I would never have begun to publish, to teach, to undertake research. Because if one does not find an assenting echo to one’s ideas, if one is passed over, as I was in Vienna, then one cannot create. To create, after all, is to believe that what one says will count.”
—Margaret S. Mahler (1897–1985)
“A work of art is an echo chamber which repeats what people say about it.”
—Mason Cooley (b. 1927)
“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)