These wavelengths are typically a few feet long in the FM band and up to 600 yards or more in the AM band. Radio stations transmit electromagnetic radiation, not sound. The radio station encodes a pattern on the electromagnetic radiation it transmits, and then our radios receive the electromagnetic radiation, decode the pattern and translate the pattern into sound. New instrumentation and computer techniques of the late 20th century allow scientists to measure the universe in many regions of the electromagnetic spectrum. We build devices that are sensitive to the light that our eyes cannot see.
Light travels in the form of a wave.
It is important to be familiar with the general anatomy of a wave to understand the relationship of wavelength to energy. The lowest part of the wave is called a trough. The highest part of the wave is the crest. The amplitude is the height of a wave. A wavelength is the distance from two corresponding points on subsequent waves, for example, from crest to crest or from trough to trough.