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.