• Sound waves are transmitted via the vibrations of air molecules

• They transfer energy by the molecules vibrating and knocking into neighbouring molecules

  • That's why sound waves travel fastest in solids(particles are close together) and slowest in gases.

• Sound is an example of a longitudinal wave, hence it consists of:

  • Compressions - regions of higher density
  • Rarefactions - regions of lower density

  

  The Y shaped thingy is a tuning fork, it is commonly used for these experiments

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

  • Wave speed $(v)$
  • Frequency $(f)$
  • Wavelength $(λ)$

Refraction of Sound

• When sound moves from a denser medium to a rarer dense medium:
  • The wavelength of the sound wave increases
  • The frequency of the sound wave stays the same (as it depends on the source)
  • The velocity of the sound wave increases
• When sound moves from a rarer medium to a denser medium:
  • The wavelength of the sound wave decreases
  • The frequency of the sound wave stays the same (as it depends on the source)
  • The velocity of the sound wave decreases