Demonstration of the Doppler Effect The principle of the Doppler effect is an important part of the fundamental nature of Mussbauer rpeetruscopy.' An acoustic demonstration is very effective in giving an intuitive feeling for the Doppler shift People used to be familiar with the increase in pitch of a train whistle as it came toward one and the decrease m piteh as it went away, but trains are not as familiar any more. An electric shaver held f m l y in the hand is convenient and effective in demonstrating the Doppler effect. If the shaver is held still. a constant itch (with some noise) is heard hv the class. If the hand holding the shaver is then thrust vigorously townrdihe class, anincrease in pitch is heard hy them if the shaver is pulled viRorourlysway from the class, a decrease in piteh is heard. The hert demonstration is to divide the class into two groups about twenty feet apart with the demunstratnr in the center. If the shaver is moved vigorously away from one group toward the other, one group will report an increase in piteh while the other observes aderrease. While it k necessary to move the shaver vigorously to ohserve the effect, no great athletic ability is needed. Every student in a m o m of thirty was ahle to observe the effect, so no special musical talent is needed by the students either. A tuning fork would give a purer tone hut is not loud enough for a classroom and does not maintain a constant volume. ~
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1 Goldanskii, V. I., and Herber, R. H., "Chemical Applications of M6ssbauer Spectroscopy," Academic Press, New York. 1968. pp. 9-15.
M i c h i a n Technological University Houghton. 49931
Dean C. Luehrs J o a n M. Luehrs
Volume 52, Number 9. September 1975/ 567
