• What the different types of waves are
• Interference of two waves
• The reflection of waves on a spring
• The concept of standing waves
• The cause of the Doppler Effect

Directions: Check out the links within each titled section, then answer the questions. More importantly, understand the answers to each question. (Let me know if there are any links that do not work.)

Basic Wave Phenomena

• What is a Wave? - a disturbance which travels through a medium
• Longitudinal and Transverse Waves - Particle Motion for Longitudinal, Transverse, Water and Rayleigh Surface Waves
• Introduction to Waves
• Parts of a Wave - Shows the parts of a transverse wave.
• Frequency of Waves

1. What is a "wave"? What is necessary for a wave? How do particles within the medium travel? How do they NOT travel?
2. For each type of wave listed, describe how the particles are moving relative to the direction the wave is traveling (direction of "propagation"). Longitudinal, Transverse, Water Waves.
3. Explain why longitudinal and transverse waves are named the way they are.
4. What are areas of "compression" and "rarefraction"?
5. What happens to the motion of the particles in a water wave, as the depth increases?
6. Using a diagram, label the parts of a transverse wave, including crest, trough, amplitude (+ and -), phase, and the three ways to measure the wavelength.
7. Define the "frequency" of a wave.

Interference

• Superposition of Two Waves - Interference, Standing Waves, and Beats. Study these for a while, you may actually start to understand them!
• More Superposition - Control the speed and timing.
• Even More
• Wave Interference - Check out all of the crazy shaped waves colliding in this action packed site!
• Coupled Oscillators - energy transfer between two mass-spring systems coupled together

1. Do waves bounce off each other, or go through each other? Are they affected in any way after the "collision"?
2. Define the process of "superposition" of two transverse waves.
3. Explain why it was possible to hit the middle cup in the spring exercise, but not hit the outer two cups?
4. Explain what is happening when two sine waves with equal wavelengths, but different phases interfere with one another. (The second animation on the "Superposition of Two Waves" link.)

Reflection

• Phase changes upon reflection from hard, soft, and mixed boundaries

1. Explain how waves reflect from hard (fixed) and soft (movable) boundries.
2. For the animation that shows reflection/transmission from high speed to low speed (low density to high density), and for the animation that shows reflection/transmission from low speed to high speed (high density to low density) - answer the following questions:

=> How do the amplitudes of the reflected and transmitted waves compare to the amplitude of the incident wave?
=> How do the polarities of the reflected and transmitted waves compare to the polarity of the incident wave?
=> How do the widths of the reflected and transmitted waves compare to the width of the incident wave?

Standing Waves

• Superposition of Two Waves (Check out the standing wave animation.)
• Excellent Standing Waves - It doesn't get any better.
• From Reflections
• Vibrational Modes of a Hanging Chain - mode shapes for a hanging chain
• Vibration of a Fixed-Fixed String - mode shapes, and frequency spectra for a plucked string
• Rectangular Membrane - and degenerate modes of a square membrane
• Circular Membrane - or how a drum head vibrates
• Vibration of Baseball Bats - bending modes (sweet spot) and cylinder modes (ping)
• Vibrational Modes of an Electric Guitar - actual experimental Modal Analysis data
• Vibrational Modes of an Acoustic Guitar - actual experimental Modal Analysis data
• Tacoma Narrows Bridge - when engineers don't account for resonance when designing structures

1. What is a standing wave?
2. Explain what is necessary for standing waves to occur.
3. What is a "node", in relation to a standing wave?

Doppler Effect

• The Doppler Effect - moving sound sources and sonic booms
• Airplane Applet - Change the speed of the plane, check out the waves.
• Violin on a Train - Click on the train picture to get going.

1. Explain the Doppler Effect.
2. Define the frequency of a wave.
3. How does the frequency of sound waves relate to pitch (high vs low)?
4. What happens to the frequency of the sound waves as the noise is moving towards you? Does the pitch (not volume) change as it is moving towards you?
5. What happens to the frequency of the sound waves as the noise is moving away from you? Does the pitch change then?
6. When does the pitch actually change?
7. Discribe, in detail how the pitch (high vs low) and volume (loud vs quiet) changes.
8. What is a sonic boom? What has to be happening for one to occur?

Stop Here! We will do the rest later. Maybe.

Refraction / Internal Reflection

• Refraction of Waves
• Refraction of Sound Waves - how temperature gradients make sound waves change direction

• Sound Fields Radiated by Simple Sources - pressure sound fields produced by monopole, dipole, and quadrupole sources
• Sound Radiation from Cylindrical Radiators - particle motion and sound fields produced by vibrational modes of a cylinder
• Sound field radiated by a Tuning Fork - animations to accompany a paper submitted to the American Journal of Physics

• When Particles Behave Like Waves (in 2-D)
• Double Slit Interference for Particles! => JAVA Applet by Physics 2000
• Double Slit Interference => JAVA Applet by Physics 2000