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Sound Waves and Pressure

Investigation 3 – PreLab









This Investigation is designed to help you to answer the following Focus Question:

  • How do different types of matter affect the speed, the wavelength, and the frequency of sound? 

Note: This question is located in your SDR at the beginning and end of the Investigation.



As a class, read the Background(s) in the Investigation.When finished, discuss the following concepts as a class:

  • The speed of sound is different in different types of matter depending on how the particles of matter interact.
  • Greater attraction between particles results in a greater speed of sound in that matter.
  • Little attraction between particles results in a lower speed of sound in that matter.
  • Typically, the speed of sound is greater in solids than in liquids and greater in liquids than in gasses.
  • The unit of frequency is the Hertz which is defined as the number of vibrations that occur in one second. Hertz are therefore expressed as 1/sec.
  • The unit of wavelength is the meter and is defined as the length of the standing wave of a vibrating object and the length of the pressure wave of the sound the vibrations produced.
  • The speed of a standing wave or a pressure wave has units of meters per second.
  • The speed of a wave, its frequency, and its wavelength are all related by the following equation: Speed = wavelength x frequency



  •  There are no new Key Terms introduced in Investigation 3.

Note: Additional words may be bolded within the Background(s). These words are not Key Terms and are strictly emphasized for exposure at this time.


  • Complete the Prediction section in your SDR. 
    • Does sound have slower or faster speed in gases, liquids, or solids?
    • What properties of matter might affect the speed of sound?
    • Can you think of some examples of how the type of matter might affect the speed of sound?
  • Play the video below. Remember to follow along with your SDR and make any notes that you think might be helpful in the lab.
  • After the video, divide into lab groups to discuss strategy for the lab. For example, you may assign certain group members to perform specific functions during the lab.

Note: The purpose of the video is to allow you to anticipate the laboratory experience you will soon encounter. You should leave this PreLab session with a firm idea of what to expect and how to perform in the lab.

Note: Homework is posted below the video.


You should review the Investigation and the video in preparation for the Lab.