12/12/08

Post date: Dec 11, 2008 5:56:22 PM

Bell Activity: What did you observe when waves went over the squares of glass?

    • Refraction

      • Waves pass into an area where the wave speed is different

      • Waves hit this area with a certain frequency (so many waves each second), and frequency does not change.

      • In order to compensate for a change in velocity, wavelength must change as well

      • Ocean waves

        • In deep ocean, have long wavelengths and fast speeds, very small amplitudes

        • Near shore (shallower water), waves slow down and pile up to make taller waves with shorter wavelengths.

    • Diffraction

      • Waves will bend around the edges of particles

      • Waves will spread into circular waves when they pass through a small opening

      • When several openings are near to each other, waves pass through and diffract (spread out) then interfere with each other on the other side.

      • Matter

        • If I throw tennis balls toward a gap between two walls, the balls either bounce off and come back toward me or go straight through the gap

        • If matter behaved like waves do, when the ball went through the gap it would explode and shoot out in all directions equally!

    • Other notes:

      • Wave types

        • Mechanical waves - require a medium

        • EM waves - do not need a medium

      • Sonar

    • If matter behaved like waves...

      • Work in groups of 3-4

      • Create an example of what our world would be like if matter behaved like waves

      • Example: ball thrown through gap between walls explodes and shoots out in all directions

      • Illustrate your example and share with the class

    • Chapter 14 Review

      • Reviewing Concepts: 3, 5, 10, 14, 17, 21

      • Applying Concepts: 1, 3, 6

      • Problems: 1, 4, 6, 8, 13, 15

  • Quiz on Monday - 25 points, covering chapter 14

      • For 5 bonus points on the quiz, draw a picture of what the world would be like if matter behaved like waves

        • We've discussed several "wave behaviors" so far, your picture should show what matter would look like if it were behaving in one of those ways.

        • Drawing must be in color

        • Include a short description of what's happening in the picture to show a wave behavior