Sound Intensity and Sound Pressure Level By:Nathalia BeniteZ


Sound intensity is the sound power per unit area. This is used as a measurement of sound intensity in the air at a persons location. The units are decibles (dB) or watts/m^2. Its formula that is used for measurements is Intensity I. The most common sound intensity measurement that is used is the decibel scale.

Sound pressure levels consist of sound waves which are related to its amplitude. Sound waves are produced by some vibrations; the greater its pressure amplitude, the more the air is compressed (louder) in the sound it creates. The pressure variations are measured in units N/m^2. Pressure variation is equal to amplitude.


Sound intensity level B
Intensity of sound


  1. Sound Intensity: measure of the flow of sound, power per unit area carried by a wave.
  2. Decibles: a unit that is used to measure the sound level
  3. Logarithm: a quantity representing the power to which a fixed number (the base) must be raised to produce a given number.
  4. Sound Intensity Level B: Sound having an Intensity I (watts/m^2)
  5. Amplitude: the maximum length of a vibration or oscillation.

Conceptual questions

Six members of a synchronized swim team wear earplugs to protect themselves against water pressure at depths, but they can still hear the music and perform the combinations in the water perfectly. One day, they were asked to leave the pool so the dive team could practice a few dives, and they tried to practice on a mat, but seemed to have a lot more difficulty. Why might this be?

  • The ear plugs reduce the intensity of sound in the water and on land
Sound intensity levels and intensities

A community is concerned about a plan to bring train service to their downtown from the town’s outskirts. The current sound intensity level, even though the rail yard is blocks away, is 70 dB downtown. The mayor assures the public that there will be a difference of only 30 dB in sound in the downtown area. Should the townspeople be concerned? Why?

  • The townspeople should not be worried because the sound intensity would be 20 dB which is a whisper at 1 m distance.


Created with images by totravelandbeyond - "marble background backdrop"

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