How do you measure wavelength?

Question

the science way

Answer 1

It depends on what you are measuring, if it is light, the colour will tell you what the wavelength is. In general it is just the distance between to similar points on the wave, usually peaks or troughs for conveniance.

It is usually much easier to measure frequency, and wavelength = v/f where v is the speed of the wave. For light, it is the speed of light, approx 3*10^8m/s. The wavelength of a particular red light = c/f(red) = 3*10^8/483*10^12 = 620nm.