Monday, March 12, 2012

Girl Scout Cookie Binge and A Straw Oboe

I did really good avoiding Girl Scout Cookies, until we bought a box of Trefoils and a box of Thin Mints outside a Kroger in Louisville.  The little girl was an efficient and cute salesperson.  I decided to have a few cookies with my coffee earlier this morning.  It ended with a Hunter S. Thompson style binge.  I lost time and now find myself surrounded by empty wrappers and cookie crumbs.  I’m not proud of this.  All I can do at this point is clean my face and the living room floor, rehydrate, force down some Activia and never speak of this again.  On a positive note, I’ve saved myself from thinking about the cookies by consuming them all.  I always try to be a glass half-full type of person.


Straw Oboe

What You Need
Drinking Straw

What You Do
Flatten one end of the soda straw by sticking the end in your mouth, biting down with your teeth, and pulling it out.  Do this several times to make a flexible flat-ended straw.  Cut equal pieces of straw from each side of the flat region so that the straw has two lips at the end. 

Put the straw in your mouth, and bite down on it gently with your front teeth just beyond the lips of the straw.  Experiment with blowing hard and softly while biting down with different amounts of pressure until you make the straw sing.

What is Going On?
When you blow, a pulse of compressed air flows down the straw.  The pulse travels down the straw at Mach 1, the speed of sound, and bounces off the distant open end.  When the sound bounces off the open end, the compressed air changes into a low-pressure expansion.  When the expanded air reaches the lips of the straw, they are forced closed – then bounce open to admit more air.  The sound bounces back and forth inside the straw and the lips of the straw open and close to create sound.

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