Many science textbooks (and government documents -- for example, that at http://www.ntia.doc.gov/osmhome/allochrt.html
) contain a rather silly error -- the confusion and merging of audible and electromagnetic
Contrary to popular belief, the spectrum of electromagnetic radiation does NOT include an audible
range of sonics, ultrasonics, and infrasonics. There is no reason to even
mention such a thing on a chart of the electromagnetic spectrum. No matter how high pitched a sound one makes, it's
still vibrations of air (or other media) molecules -- it'll never be a
radio wave. No matter how low-frequency the radio wave is, it's still an
electric and magnetic field -- it'll never be a sound.
No matter how high you scream, it's not going to come out blue.