WE HAVE LEARNED THAT ALL STATIC PHYSICAL THINGS CAN
BE MEASURED AND THUS DESCRIBED BY NUMBERS.  HOWEVER WHEN
SOMETHING IS CONSTANTLY CHANGING WE MUST USE ALGEBRAIC
EQUATIONS TO EXPRESS THE RELATIONSHIPS INVOLVED.  IN THIS
WAY WE CAN FIND THE NUMBERS WHICH WILL DESCRIBE THE
PARTICULAR STATE OF THE CHANGING THING AT ANY FROZEN MOMENT
IN TIME.
 
      SOUND IS PRODUCED BY RAPID CHANGES OF AIR PRESSURE IN
THE EAR.  WHEN THESE CHANGES ARE VERY GREAT WE SAY THE
SOUND IS LOUD.  WHEN THEY ARE IRREGULAR WE SAY THE SOUND IS
NOISE.  WHEN THE CHANGES ARE VERY REGULAR AND SMOOTH WE SAY
THE SOUND IS MUSICAL.  THERE ARE SIMPLE FORMULAS WHICH CAN
EXPRESS THE PATTERN OF CHANGE IN AIR PRESSURE FOR A MUSICAL
SOUND.  BY USING SUCH FORMULAS THE COMPUTER CAN PRODUCE A
LONG STRING OF NUMBERS WHICH GIVE A CLOSE APPROXIMATION OF
THE CHANGING AIR PRESSURE OF A MUSICAL NOTE.
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