Sound

• The wavelength of a sound wave is the distance between two consecutive points in phase, such as two compressions or two rarefactions.
• Sound is a longitudinal wave that travels through the air or other medium.


  What type of wave is sound
• Waves can be classified by their frequency, which is measured in hertz (Hz), where one cycle occurs every second.
• Frequency is defined as the number of waves passing a given point per unit time.
• Amplitude refers to how far apart are the peaks and troughs of a wave from its equilibrium position.
• The ear canal channels the sound waves to the eardrum. This can get blocked by wax.
• Sound waves in the air make the ear drum vibrate. This part of the ear can get damaged by infections.
• Ossicles are bones which pass on the vibrations from the ear drum. These parts can fuse together as you get older (ostoclerosis)
• The cochlea are tiny hairs which convert vibrations into electrical impulses. This can be damaged by accidents or sudden loud noises.
• Electrical impulses travel along this to the brain. This part can be damaged by constant loud noises.
• Frequency = number of waves / time

  F = n / t
• Ultrasound is any frequency of a sound that is over 20000Hz
• Infrasound is any frequency below 20Hz and is not heard by humans.
• Label the following:

  
• Period of a wave is the time taken for one complete oscillation of the wave.

  f = 1 / T
• Pitch is the frequency of a sound waves.

  Loudness is a measure of the amplitude of a sound wave.

  
• Space is a vacuum meaning that there are no particles. Sound needs particles to vibrate and cause waves so sound can't be heard in space.
• Wave speed = frequency x wavelength (m/s)
• Sound travels faster through solids than liquids or gases because the molecules in solids are closer together and have less freedom to move around compared with those in liquids and gases.