ELECTROMAGNETIC-WAVES IN-SPACE - VISUALIZATION OF E AND B, AND PEDAGOGICAL APPROACHES USING SUPERPOSITION

A beam of electromagnetic waves, produced by a ''ham'' transmitter at a frequency just below 450 MHz, is studied using a pair of antennas, o ne an electric and the other a magnetic ''dipole.'' each coupled to su bminiature lamp bulb. These bulbs become very brightly lit in response to the local time average values of \E\(2) and \B\(2), respectively. Most strikingly, the interleaving of the electric and magnetic oscilla tion maxima in a standing wave is seen. This and other aspects of the phenomena are described using an accompanying pedagogical approach whi ch emphasizes the primary idea of wave superposition. (C) 1997 America n Association of Physics Teachers.