Max Planck’s Cosmic Harmonium

November 14, 2013

HARVARD PHYSICS MONDAY COLLOQUIUM
Peter Pesic, Musician-in-Residence, St. John's College, Santa Fe, NM; Associate of the Department of Physics, Harvard Universit
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In 1893, Max Planck, newly appointed professor of physics in Berlin, was seconded to study the department’s Eitz harmonium, capable of dividing an octave into 104 steps. An accomplished musician, Planck learned to play this new instrument and used it to devise experiments in musical temperament, the only experiments he ever conducted in a career devoted to theoretical work. Planck’s "experiments" consisted of short musical compositions testing whether or not singers would revert to "natural" (just) tuning as opposed to the equal-tempered scale in common use. His surprising results contradicted his expectations and those of his teacher Hermann von Helmholtz: the habit of equal temperament was stronger than the pull of "natural" temperament. The following year (1894), the "black year" of German physics, left Planck the only surviving professor in his department through the premature deaths of Heinrich Hertz and August Kundt. Planck then turned to the problem of blackbody radiation, for which his musical experiments prepared him by alerting him to the power of habitual assumptions as well as by providing him the detailed example of a harmonium with tunable resonators, comparable to Hertzian oscillators. The modes of electromagnetic waves in a cavity have many analogies with the problems of tuning and temperament Planck had just studied. His investigations of universal "natural" temperament led directly to his work proposing a new "natural" tuning of atomic resonators, from which Planck drew the consequence of a truly universal "natural" system of cosmic units.

Monday, November 18 @ 4:15PM
Jefferson Lab 250, 17 Oxford Street, Cambridge, MA 02138