1. Waves & Sound

2. Single Medium  The speed of a wave is dependent on the medium. Some factors that can affect wave speed are density, rigidity, state, and viscosity.  Two waves on a collision course will pass through each other without any permanent effect on either wave. At the point of collision, the amplitudes of the two waves will mathematically add to form a temporary waveform called a superposition.

3. Constructive Interference  Occurs when two colliding waves produce a wave form that increases the overall amplitude of the medium at that point

4. Destructive Interference  Occurs when two colliding waves produce a wave form that decreases the overall amplitude of the medium at that point.

5. Reflection of Waves  Waves will reflect at the boundaries of their media. This is why we can see walls and hear echoes. In fact most barriers reflect some amount of energy.

6. Free-End Reflections  Waves that reach the boundary of a medium (with an end free to move) will reflect a pulse back at the same speed, amplitude and orientation. i.e: Water Waves

7. Fixed-End Reflections  Waves that reach the boundary of a medium (with an end that is fixed) will reflect a pulse back at the same speed and amplitude but inverted.

8. Two Different Media  The frequency of a wave remains constant when passing from one medium to another.  From our wave equation, the wavelength depends on the wave speed. Thus: The slower the medium, the shorter the wavelength The faster the medium, the longer the wavelength  Waves that encounter boundary between two media will experience both transmission and reflection.

9. Fast to Slow Medium  The pulse traveling from the faster medium sees the boundary as a fixed- end and reflects accordingly.

10. Slow to Fast Medium  The pulse traveling from the slower medium sees the boundary as a free- end and reflects accordingly

11. References  Reflection of Waves from Boundaries: http://www.acs.psu.edu/drussell/Demos/refle ct/reflect.html http://www.acs.psu.edu/drussell/Demos/refle ct/reflect.html