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:
“The echo is, to some extent, an original sound, and therein is the magic and charm of it. It is not merely a repetition of what was worth repeating in the bell, but partly the voice of the wood; the same trivial words and notes sung by a wood-nymph.”
—Henry David Thoreau (1817–1862)
“I’ve noticed that the children of other nations always seem precocious. That’s because the strange manners of their elders have caught our attention most and the children echo those manners enough to seem like their parents.”
—F. Scott Fitzgerald (1896–1940)
“The moralist and the revolutionary are constantly undermining one another. Marx exploded a hundred tons of dynamite beneath the moralist position, and we are still living in the echo of that tremendous crash. But already, somewhere or other, the sappers are at work and fresh dynamite is being tamped in place to blow Marx at the moon. Then Marx, or somebody like him, will come back with yet more dynamite, and so the process continues, to an end we cannot foresee.”
—George Orwell (1903–1950)