Lab 8: Wave Interference
Name Date
Assignment Submission Directions: Download this assignment sheet and complete by answering all
questions. You will need to access the simulations website in order to complete the labs. When
completed, save your work and upload the document to the Assignment Upload for graded submission.
50 points.
Items in red font require submission into a pre populated text box shown as Click here to enter text.
(Note: you do not need to fill this one in, for directions purposes only.)
Simulation Link: https://phet.colorado.edu/sims/html/wave-interference/latest/wave-
interference_en.html
Part A: Wave Interference
Make waves with a dripping faucet, audio speaker, or laser! Add a second source to create an
interference pattern. Put up a barrier to explore single-slit diffraction and double-slit interference.
Experiment with diffraction through elliptical, rectangular, or irregular apertures.
Learning Goals: Students will be able to
● Make waves with water, sound, and light and see how they are related.
● Create and change an interference pattern(s) with two sources.
● Find points of constructive and destructive interference by eye and by using the detectors.
● Put up a barrier to see how the waves move through one or two slits.
● Predict how changing the wavelength or aperture size affects the diffraction pattern.
Part 1. Wave Interference Simulation
Activity
● Open the PhET simulation
‘Wave Interference’.
● Click on the ‘Waves’ option.
(At bottom on screen)
● Explore the simulation to get
a feel for the controls.
1. Experiment with the settings and choose the view that you prefer (‘Top View’ or ‘Side View’.) Try
checking the ‘Graph’ box and watch how the plot is related to the amplitude of the wave.
2. Set the frequency to the minimum. Use the ‘Timer’ to measure how long it takes for the wave to
travel the length of the box.
8 seconds
, Lab 8: Wave Interference
3. Set the frequency to the maximum. Use the ‘Timer’ to measure how long it takes for the wave to
travel the length of the box.
6 seconds
Observing Sound Waves
Now switch to observing sound waves (press the speaker icon).
● Experiment with viewing the
wave propagation.
● Explore Waves, Particles, and
Both.
4. Observe the motion of an individual particle (choose a random red dot). What can you say about its
motion as the waves pass by?
As the waves move through, the red dot is pushed away by a repulsive force and then pulled back by an
attractive force.
5. What are the particles doing when no sound pulse is traveling through?
When no sound wave is moving through, the particles stay still because there’s no wave to make them
move. This makes sense because there are no vibrations causing any noticeable motion.
6. What makes it realistic?
The simulation is realistic because it shows how particles move back and forth when a wave passes
through. It also demonstrates how particles get closer together (compression) and farther apart
(rarefaction), just like how waves work in real life.
Utilize the Measuring Tape Application
● Select the measuring tape application.
7. Set the frequency to the minimum. Measure the wavelength and record it
here. 52 cm
8. Set the frequency to the maximum. Measure the wavelength and record it
here. 34 cm
Name Date
Assignment Submission Directions: Download this assignment sheet and complete by answering all
questions. You will need to access the simulations website in order to complete the labs. When
completed, save your work and upload the document to the Assignment Upload for graded submission.
50 points.
Items in red font require submission into a pre populated text box shown as Click here to enter text.
(Note: you do not need to fill this one in, for directions purposes only.)
Simulation Link: https://phet.colorado.edu/sims/html/wave-interference/latest/wave-
interference_en.html
Part A: Wave Interference
Make waves with a dripping faucet, audio speaker, or laser! Add a second source to create an
interference pattern. Put up a barrier to explore single-slit diffraction and double-slit interference.
Experiment with diffraction through elliptical, rectangular, or irregular apertures.
Learning Goals: Students will be able to
● Make waves with water, sound, and light and see how they are related.
● Create and change an interference pattern(s) with two sources.
● Find points of constructive and destructive interference by eye and by using the detectors.
● Put up a barrier to see how the waves move through one or two slits.
● Predict how changing the wavelength or aperture size affects the diffraction pattern.
Part 1. Wave Interference Simulation
Activity
● Open the PhET simulation
‘Wave Interference’.
● Click on the ‘Waves’ option.
(At bottom on screen)
● Explore the simulation to get
a feel for the controls.
1. Experiment with the settings and choose the view that you prefer (‘Top View’ or ‘Side View’.) Try
checking the ‘Graph’ box and watch how the plot is related to the amplitude of the wave.
2. Set the frequency to the minimum. Use the ‘Timer’ to measure how long it takes for the wave to
travel the length of the box.
8 seconds
, Lab 8: Wave Interference
3. Set the frequency to the maximum. Use the ‘Timer’ to measure how long it takes for the wave to
travel the length of the box.
6 seconds
Observing Sound Waves
Now switch to observing sound waves (press the speaker icon).
● Experiment with viewing the
wave propagation.
● Explore Waves, Particles, and
Both.
4. Observe the motion of an individual particle (choose a random red dot). What can you say about its
motion as the waves pass by?
As the waves move through, the red dot is pushed away by a repulsive force and then pulled back by an
attractive force.
5. What are the particles doing when no sound pulse is traveling through?
When no sound wave is moving through, the particles stay still because there’s no wave to make them
move. This makes sense because there are no vibrations causing any noticeable motion.
6. What makes it realistic?
The simulation is realistic because it shows how particles move back and forth when a wave passes
through. It also demonstrates how particles get closer together (compression) and farther apart
(rarefaction), just like how waves work in real life.
Utilize the Measuring Tape Application
● Select the measuring tape application.
7. Set the frequency to the minimum. Measure the wavelength and record it
here. 52 cm
8. Set the frequency to the maximum. Measure the wavelength and record it
here. 34 cm
