Wavelength> Does a sound have a size? Are there foot-long sounds? There are! The size of a sound wave is called its <#5657,5101><!wavelength>. And along with <#5680,7><!frequency> and <#5681,8><!amplitude>, wavelength is a property of <#5675,6><!waves> that sound and water both share.
Toss that pebble in the pond once more, and look at how the water wave spreads out across the surface. Take a flash snapshot at just one instant. The water surface is wrinkled into crests and troughs. The distance across the surface from one crest of the wave to the next is the wavelength of that wave. A pond water wave might be a few inches from crest to crest, or a few feet. Waves come in many different wavelengths.
Sound waves also have a wavelength - you just can’t see it as easily because sound wave vibrations are invisible. But the waves that move from a flute or a saxophone have a regular spacing, or wavelength, just like water waves.
For all waves, frequency, wavelength and speed are related to each other. If you multiply the frequency times the wavelength, you will always get the speed of the wave! You can figure out the wavelength of a sound if you know its <#5678,4><!speed> and its <#5680,7><!frequency>. The sound of “middle C” on the piano has a frequency of about 523 Hz and a wavelength of about 2 feet! That low “thrummmm” from the string bass? 40 Hz and a wavelength of 25 feet! That’s a sound wave that will barely fit in a room!
