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WebLab: Exploring Waves with PhET Colorado

Objective
To understand the properties of waves, including frequency, amplitude, and wavelength, using the PhET “Wave on a String” simulation.
Materials
● Computer with internet access
● PhET “Wave on a String” simulation: Wave on a String - PhET Interactive Simulations1


Procedure
1. Access the Simulation: Open the PhET “Wave on a String” simulation in your web browser.
2. Initial Setup: click the play button.
○ Click the pause button near the center bottom
○ Set the simulation to “Oscillate” mode.
○ On the right side select “No End”
○ Adjust the damping (friction) to “None” and tension to “High”.
3. Exploring Frequency and Amplitude:
○ Set the frequency to 1.00 Hz and amplitude to 0.60 cm.
○ Click the play button and observe for a moment, try to follow a wave to see its speed.
○ Now click pause. Click ruler and measure the length of one wavelength. What is the approximate value of the wavelength?🚩

○ Increase the frequency to 2.00 Hz and click play. What happens to the wavelength when the frequency increases?🚩

It is difficult to measure the speed of the wave but changing the frequency does not change how fast the wave is moving.

4. Investigating Wavelength:
○ Set the frequency to 1.25 Hz and amplitude to 1.25 cm. Click play and observe.
○ Hit pause and measure the wavelength using the ruler tool in the simulation.🚩

○ Change the tension to “Low”, hit play and observe how the wavelength changes. Closely follow an individual wave crest, does each individual wave crest travel faster or slower when the tension is higher? 🚩

5. Damping Effects: Damping is friction
○ Set the damping to “Lots” and observe how the wave dissipates over time.
How does damping affect wave propagation?🚩

Going further: do some quick research.
Waves carry energy, research and describe which property of a wave determines its energy.🚩

When you turn up the volume on some airpods, what part of the sound wave changes?🚩

1 answer

WebLab: Exploring Waves with PhET Colorado

Objective

To understand the properties of waves, including frequency, amplitude, and wavelength, using the PhET “Wave on a String” simulation.

Materials

Procedure

  1. Access the Simulation: Open the PhET “Wave on a String” simulation in your web browser.

  2. Initial Setup:

    • Click the play button.
    • Click the pause button near the center bottom.
    • Set the simulation to “Oscillate” mode.
    • On the right side, select “No End.”
    • Adjust the damping (friction) to “None” and tension to “High.”

  3. Exploring Frequency and Amplitude:

    • Set the frequency to 1.00 Hz and amplitude to 0.60 cm.

    • Click play and observe for a moment, trying to follow a wave to see its speed.

    • Now click pause. Use the ruler to measure the length of one wavelength.

      • Approximate value of the wavelength: (measure using the ruler tool in the simulation, typically around 60 cm, but this may vary slightly based on your observation).

    • Increase the frequency to 2.00 Hz and click play.

      • Observation: As the frequency increases, the wavelength decreases. This is a reflection of the inverse relationship between frequency and wavelength (higher frequency results in shorter wavelength while wave speed remains constant).

  4. Investigating Wavelength:

    • Set the frequency to 1.25 Hz and amplitude to 1.25 cm. Click play and observe.

    • Hit pause and measure the wavelength using the ruler tool in the simulation.

      • Approximate wavelength measurement: (again, measure this based on your observation).

    • Change the tension to “Low,” hit play, and observe how the wavelength changes.

      • Observation on tension: As tension decreases in the string, there is typically an increase in wavelength. Following an individual wave crest reveals that each crest travels slower when the tension is lower.

  5. Damping Effects: Damping is friction.

    • Set the damping to “Lots” and observe how the wave dissipates over time.
      • Effect of damping: Higher damping results in greater energy loss over time, weakening the wave and causing it to fade away more quickly. This shows how damping reduces the amplitude of the wave, thus affecting wave propagation.

Going Further: Research

  • Waves Carry Energy: The property of a wave that determines its energy is the amplitude. A higher amplitude means that the wave carries more energy. In mechanical waves, greater amplitude indicates more energy is being transferred through the medium.

  • Sound Waves and Volume: When you turn up the volume on devices like AirPods, you are increasing the amplitude of the sound waves being produced. The greater the amplitude, the louder the perceived sound, as higher amplitude results in a larger pressure variation in the air that your ears detect.

These observations and explanations provide a fundamental understanding of wave properties as well as real-world applications for sound waves. If you have any further questions or need clarification on any point, feel free to ask!