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Frequency and Wavelength

Author: N.H. Crowhurst

All sounds travel at the same speed, regardless of frequency. Because the waves are traveling, the length of a wave (measured along the direction it travels) from the peak of one wave to the peak of the next will be different, according to the frequency.

 Wavelength and frequency

Sound moves at about 1100 feet per second. If the frequency of a sound is 440 cycles per second (A above middle C), there must be 440 cycles in a 1100-foot piece of the sound wave. Each wave is thus about 2^4 feet long in this case. If the frequency is 8800 cycles (an octave beyond the end of a piano keyboard) the same space (1100 feet) will be occupied by 8800 cycles, or waves, and each must be only one eighth of a foot (about \y2 inches) long. Low frequencies from organ pipes may be down in the region of 32 cycles, with a wavelength of 34 feet.

Last Update: 2010-11-03