1. Discover Activity How do you think the angle at which the ball hits the wall is related to the angle at which the ball bounces back?

2. Interactions of Waves

3. In Red book, read pages 366-367 Define: Reflection

4. ReflectionReflection When an object or a wave hits a surface through which it cannot pass, it bounces back. The LAW OF REFLECTION states that the angle of incidence equals the angle of reflection.

6. Test it out… How do you think the angle at which the ball hits the wall is related to the angle at which the ball bounces back? Will the ANGLE OF INCIDENCE equal the ANGLE OF REFLECTION?

7. In Red book, read pages 368-369 Define: Refraction

8. RefractionRefraction When a wave enters a new medium at an angle, one side of the wave changes speed before the other side, causing the wave to bend.

9. DiffractionDiffraction When a wave moves around a barrier or through an opening in a barrier, it bends and spreads out.

10. InterferenceInterference The interaction between waves that meet. Constructive Interference: When waves combine to make a wave with a larger amplitude. Destructive Interference: When waves combine to make a wave with a smaller amplitude.

11. Standing Waves Standing Waves *Write in notebook* Standing Waves Standing Waves Standing Waves *Write in notebook* Standing Waves A wave that appears to stand in one place, even though it is really two waves interfering as they pass through each other. Node: Points of zero amplitude on a standing wave that are always evenly spaced along the wave. Antinode: Points of maximum amplitude on a standing wave that always occur halfway between two nodes and have maximum energy.

12. Resonance *Write in notebook* An increase in the amplitude of a vibration that occurs when external vibrations match an objects natural frequency..

13. Ha ha ha…