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:
“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)
“Art for art’s sake? I should think so, and more so than ever at the present time. It is the one orderly product which our middling race has produced. It is the cry of a thousand sentinels, the echo from a thousand labyrinths, it is the lighthouse which cannot be hidden ... it is the best evidence we can have of our dignity.”
—E.M. (Edward Morgan)
“Bondage is hoarse and may not speak aloud,
Else would I tear the cave where Echo lies
And make her airy tongue more hoarse than mine
With repetition of “My Romeo!””
—William Shakespeare (1564–1616)