How Different are Sounds from a Phone, a Computer, and a Mouth?

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Updated on Aug 31, 2012

Grade Level: 7th-9th; Type: Physical Science


Find out the differences (if any) in the frequencies of voices produced from a computer, from a phone, and directly coming out of the voicebox of a human.

Research Questions:

  • How does an oscilloscope work to determine sound frequency?
  • What are the typical voice frequencies of men and women?

Each thing around us has a natural sound frequency that causes it to vibrate, which is called resonant frequency. When you force energy onto a material, you will cause it to vibrate and the vibrations will travel through the material and into the air molecules. As it travels through the air molecules, sound waves are produced, and that is the sounds that we hear with our ears.


  • A computer
  • A phone with the “speaker” option
  • Oscilloscope (you can get the handheld version at about $150 a piece online)
  • Microphone
  • A set passage for all your test subjects to read (can be any passage)
  • Test subjects (about 10 or more)
  • Pen and paper for notes

Experimental Procedure

  1. Choose a passage for your test subjects to read. Everyone should read the same passage, though the content of the passage doesn't matter.
  2. Use the “record” option on the computer and record your test subject reading the passage. Make sure to tell them to read it at their normal voice.
  3. Use the “record” option on the phone/cellphone and record your test subject reading the passage (once again at normal voice.)
  4. Plug in the oscilloscope and attach a microphone to it (please refer to the manual of your oscilloscope for operational instructions), turn it on.
  5. Ask your test subject to read the passage once more. Read the frequency of the voice and record this frequency.
  6. Now analyze the frequencies of the recorded voices in steps 2-3 in the computer and in the phone, also by using the oscilloscope.
  7. Repeat steps 2-6 for all your test subjects.
  8. Note any changes in frequencies.
  9. Record and analyze your results.

Terms/Concepts: Frequency; Voice; Oscilloscope; Soundwaves; Voicebox/larynx


The Science Book of Sound, by Neil Ardley (Houghton Mifflin Harcourt Publishing, 1991)
Sofia PC is currently a college student with a deep interest in science who is aspiring to become a writer.

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