Name_______________________ 20 Lab Points
Standing Waves
Learning Target:
I can explain how a standing wave is formed.
I can mathematically analyze a situation involving a standing wave to relate wavelength, frequency, and wave speed.
Part 1: Standing Waves on a String
PreLab:
How do standing waves form?
One wavelength is the space between _____ nodes and contains ______ antinodes.
Data:
Turn the apparatus on to manual mode.
1. Place the arms 31 cm apart and vary the speed at low, medium, and high.
What do you notice about the standing wave pattern when the motor speed is…
Low ________________________________________________________________________
Medium _____________________________________________________________________
High ________________________________________________________________________
2. Play around with the settings to see how many antinodes you can get.
What is the highest number of antinodes you can get with the apparatus?
Width of Arms (cm)
# of Nodes
# of Antinodes
Wavelength
3. Move the arms to achieve different numbers of antinodes.
Width of Arms (cm)
# of Nodes
# of Antinodes
1
2
3
Wavelength
Part 2: Slinky Standing Waves
Roles:
Shaker: Move the slinky from one end of the tile to the next. Vary the frequency to achieve the
proper amount of antinodes.
Stabilizer: One person should hold the other end of the slinky still.
Time Keeper: One person should measure the time it takes for 10 oscillations. This person
should also measure the wavelength
# of Antinodes
Wavelength (m)
Frequency (1/s)
(f = 10/seconds)
Wave Speed (m)
1
2
3
What is the average wave speed?
If you wanted to make 4 antinodes,
a. what would the wavelength be?
b. What frequency would you need to oscillate the slinky?
Post Lab:
Does the speed of the wave change? Does your data make sense with what you know about
waves?
What is the relationship between wavelength and frequency?
What causes nodes and antinodes to form?