12/18/08

Post date: Dec 29, 2008 12:14:8 AM

• • Review sound waves

  • Beats

    • Two sound waves with frequencies close together produce beats; we hear this as the sound getting louder and softer (wah-wah-wah-wah)

    • Used to tune musical instruments

    • Beat frequency is the difference between the two frequencies

    • f(beat) = f1 - f2

      • beat frequency is always positive

      • can solve for one frequency if we know the other and the beat frequency

      • Humans can hear beats with frequencies up to 8-9 Hz, but no higher

  • Sound Waves Quiz

    • Will be on friday

    • If classes are cancelled Friday, the quiz will become a take-home quiz

    • I will post the quiz on the "handouts" page, and you can work on it over break if you like

    • Otherwise, I'll hand out the quiz on Monday when we return and it will be due Wednesday