4/7/09

Post date: Apr 07, 2009 1:26:7 AM

Bell Ringer: Why does the laser bounce around when we reflect it off a speaker that is playing?

    • Sound waves

      • Vibrations in the air

        • Caused by vibrating object (string, drum head, speaker, etc.)

        • Laser speaker demo

      • The wave shape represents pressure, or density

        • Changes in pressure seen with spinning sound tubes sucking up bits of paper (also can be used to demonstrate Doppler effect)

        • Changes in pressure - flame tube

      • Sound created depends on a variety of factors with instruments

        • What material

        • How vibration is made

        • Playing technique

        • Example - banjo

        • Example - Blue Man Group DVD

  • Waves Review

      • Due tomorrow before test

      • Very similar to test questions