Klarinet Archive - Posting 000686.txt from 1998/09

From: Edinger/Gilman <wde1@-----.com>
Subj: [kl] heat expansion
Date: Sat, 19 Sep 1998 20:16:47 -0400

"When the wood expands, the diameter SHRINKS."

Whoops. Recall your high school physics days, when you heated the iron
ring with the ball that just barely failed to fit through it when both
were at room temperature. You heat the ring, and what happens? Does
the hole shrink? No, it expands too, because if it were to shrink
(decrease in diameter), it would become MORE compressed. The ball now
goes through because the ring - analogous to a cross-section of a
clarinet bore - expands evenly throughout. So, if it were significantly
expandable (which I don't believe it is), a wood bore would increase
with warming, not decrease. But Dee had it right, I think, when she
pointed out that the air temperature differences are the critical
factors.

Bill Edinger

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