Physics of the Blues
by Gail Cowan
Like Einstein, Argonne's Murray Gibson is a physicist whose
life's work includes finding patterns among atoms. The love
of distinguishing patterns also drives Gibson as a musician and Blues
enthusiast.
Gibson, associate laboratory director for scientific user facilities,
was drawn to playing the guitar as a child, and he later studied
piano. His mother wanted him to attend classical concerts, but — being
a child of his time — he preferred popular music. As a college
student, he spent a summer in Chicago, playing piano at the Essex
Inn for $25 a night. Always a jazz fan, Gibson discovered that his
true musical love was the “gut music” of the Blues.
As a physics professor at the University of Illinois, Gibson found
the perfect place to enjoy the intersection of music and physics.
The university's science studies were mostly located north
of Green Street — the main street across Urbana and Champaign — and
the humanities were housed to the south. The Espresso Royale coffeehouse
in the middle attracted some of the university's most interesting
people in both disciplines, and Gibson met there regularly with his
graduate students.
In looking at commonalities between music and science, Gibson describes
the musician's palette as based on the principles of physics.
He cites the musical scales that musicians use to create and play
music as such a set of rules. What makes music interesting, Gibson
says, is how musicians develop those rules and create ambiguity with
them.
And sometimes, he points out, new rules must be made to allow creativity
to grow.
Gibson cites the evolution of musical scales through the centuries
as one example. The Baroque scale was used by musicians until the
17th century, when J.S. Bach led the use of a new palette on which
to compose. He exploited the now classic “equal-temperament” scale
that has permanently altered the sound of Western music.
A more recent example would be the creation of Blues notes that
don't even exist on the Western musical scale. To create the
new sound of Blues while playing in New Orleans' houses of
ill repute, “Jelly Roll” Morton “crushed” notes,
playing notes like E and E flat simultaneously. To the cultured ears
of his day, Jelly Roll Morton's sound was crass and disgusting.
But the more mainstream Scott Joplin, by playing those two notes
right next to each other, had merely suggested the new sound and
was thereby able to bring Ragtime music into upper-class drawing
rooms — and ultimately into our culture's shared musical
lexicon.
So how does the evolution of scales and the creation of new sounds
by a turn-of-the-century bordello musician relate to physics?
"Blue” notes are very harmonic notes that are missing
from the equal temperament scale. The techniques of piano blues and
jazz represent the melding of African and Western music into something
totally new and exciting.
All music is created by using principles of mathematics and physics.
The pitch of a musical note is determined by the frequency of the
sound wave — and that's physics.
Harmony in music is based on physical principles, and there's
a harmony, a poetry to mathematics and science as well,” Gibson
says.
The sound wave comes from a vibrating object, such as on a guitar,
violin or piano, or a column of air, as comes from a flute, a trumpet
or an oboe. The frequency depends inversely on the wavelength of
the vibration — the shorter the wavelength, the higher the
frequency. For a vibrating string, all the harmonics, or overtones,
are simple multiples of the fundamental frequency, or pitch. When
you hear the pitch of a note, you are actually measuring its frequency.
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