Transmission of Sound Waves (AQA GCSE Physics)

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Transmission of Sound Waves

  • Sound waves are longitudinal waves
    • They transfer energy by the molecules vibrating and knocking into neighbouring molecules

  • The more molecules that are present the faster the wave can transfer energy, therefore:
    • Sound waves travel fastest in solids
    • Sound waves travel slowest in gases

  • When sound waves move from one medium to another, there will be changes to its:
    • Wave speed
    • Frequency
    • Wavelength

  • The relationship between the wave speed, wavelength and frequency can be determined using the wave equation
  • This change in velocity can also result in a change of direction of the sound wave
    • This phenomenon is also known as refraction

Refraction of Sound

  • When sound moves from a denser medium to a less dense medium:
    • The wavelength of the sound wave decreases
    • The frequency of the sound wave stays the same
    • The velocity of the sound wave decreases
  • When sound moves from a less dense medium to a denser medium:
    • The wavelength of the sound wave increases
    • The frequency of the sound wave stays the same
    • The velocity of the sound wave also increases
  • The speed of sound in air is also affected by temperature
    • On warm days, air molecules move faster, hence they carry sound waves faster, increasing the speed of sound
    • On cold days, air molecules move at a slower pace, so they carry sound waves at a slower pace, decreasing the speed of sound

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Ashika

Author: Ashika

Expertise: Physics Project Lead

Ashika graduated with a first-class Physics degree from Manchester University and, having worked as a software engineer, focused on Physics education, creating engaging content to help students across all levels. Now an experienced GCSE and A Level Physics and Maths tutor, Ashika helps to grow and improve our Physics resources.