Wave Webquest
Objectives: Students will gain a better understanding of the following
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What the different types of waves are
Interference of two waves
The reflection of waves on a spring
The concept of standing waves
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
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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. How are the particles moving relative to the direction the wave is traveling (direction of
"propagation")?
a) Longitudinal
b) Transverse
c) Water Waves.
3. What happens to the motion of the particles in a water wave, as the depth increases?
4. What are areas of "compression" and "rarefaction", and in which type of wave do they
apply?
5. Using a diagram, label the parts of a transverse wave, including crest, trough, amplitude ,
phase, and the three ways to measure the wavelength.
6. Define the word "frequency".
7. What are "periodic waves"?
8. How does frequency apply to periodic waves?
9. How does increasing the wavelength affect the frequency?
10. How does increasing the wave speed affect the frequency?
Reflection and Refraction
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Phase changes upon reflection from hard, soft, and mixed boundaries
Compare the waves as the undergo reflection and refraction by completing the table:
Situation
Comparison
Reflect from
hard boundary
Reflect from
soft boundary
Mixed
boundary (low
density or high
density)
Mixed
boundary (high
density to low
density)
Incident wave and
reflected wave
Incident wave and
reflected wave
Incident wave and
reflected wave
Incident wave and
transmitted wave
Incident wave and
reflected wave
Incident wave and
transmitted wave
Amplitude
(larger, smaller,
same size)
Polarity
(upright or
inverted)
Wavelength
Speed
(larger, smaller,
same size)
(faster,
slower, same)
Interference
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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.)
Standing Waves
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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?
Diffraction
Wave Interference – set up simulations to represent diffraction
1. Run the wave interference simulation. Line up frequency and amplitude two-thirds of
the way along the slider. In the water situation with one drip create two slits, less than
2.5 cm slit width, barrier located at 3.1 cm and a slit separation less than 4.2 cm. Run
the simulation and then after a few seconds pause it. Draw a sketch of what you see.
2. Change from water to light waves and repeat the instructions above (one light-two slits).
Does the diffraction pattern change for either water or light waves?
3. Reset the light waves simulation and show the screen and graph. Add a 2-slit barrier to
the simulation and allow the graphs to be formed. Observe the interference pattern
created when the characteristics of the simulation are adjusted. You may have to adjust
amplitude when other elements of the simulation are changed to observe the graph. What
effect do the following changes have on the diffraction pattern?
a. Shorter wavelength
b. larger barrier-to-screen distance
c. smaller slit width
d. smaller slit separation