GCSE Physics revision

Sound waves (physics only) (HT only)

Waves in air, fluids and solids

AQA 4.6.1.4

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AQA student objectives

Learning pathway

ALL 🎯

Describe, with examples, processes which convert wave disturbances between sound waves and vibrations in solids.

MOST 🎯🎯

Apply the scientific explanation of sound waves to a relevant example.

SOME 🎯🎯🎯

Analyse a new situation involving sound waves and explain the scientific reasoning.

Revision summary

Read on screen, then print for Cornell-style active revision.

Sound waves are vibrations that pass through the particles of a medium, making them a type of longitudinal wave.
Compressions are regions where vibrating particles are bunched closest together, whilst rarefactions are regions where particles are spread furthest apart.
Sound waves are transmitted as particles vibrate and collide with neighbouring particles, passing the vibration through the material.

1. What Are Sound Waves?AQA

Sound waves are vibrations that pass through the particles of a medium, making them a type of longitudinal wave.
Compressions are regions where vibrating particles are bunched closest together, whilst rarefactions are regions where particles are spread furthest apart.
Sound waves are transmitted as particles vibrate and collide with neighbouring particles, passing the vibration through the material.

Sound travels faster in more densely packed materials, meaning it travels fastest in solids, slower in liquids, and slowest in gases.
Sound cannot travel through a vacuum because there are no particles to vibrate and transmit the wave.
The denser the medium, the more quickly vibrations are passed between neighbouring particles, increasing the speed of sound.

2. Speed of Sound in Different MediaAQA

Sound travels faster in more densely packed materials, meaning it travels fastest in solids, slower in liquids, and slowest in gases.
Sound cannot travel through a vacuum because there are no particles to vibrate and transmit the wave.
The denser the medium, the more quickly vibrations are passed between neighbouring particles, increasing the speed of sound.

The relationship between speed, frequency, and wavelength is given by the equation v = f λ, where v is speed, f is frequency, and λ is wavelength.
When sound moves between different media, its frequency remains constant even though its speed changes.
As sound speeds up in a denser medium, its wavelength increases; as it slows down in a less dense medium, its wavelength decreases.

3. Frequency, Wavelength, and SpeedAQA

The relationship between speed, frequency, and wavelength is given by the equation v = f λ, where v is speed, f is frequency, and λ is wavelength.
When sound moves between different media, its frequency remains constant even though its speed changes.
As sound speeds up in a denser medium, its wavelength increases; as it slows down in a less dense medium, its wavelength decreases.

Sound can be refracted when it changes speed as it passes from one medium to another, just like light.
Sound can be reflected off hard, flat surfaces, producing echoes.
Sound can also be absorbed by soft materials, which reduce the amount of sound reflected.

Sound waves travel along the ear canal and cause the eardrum to vibrate.
Vibrations from the eardrum are transmitted through three small bones called ossicles, through the semicircular canals, and into the cochlea.
The cochlea converts vibrations into electrical signals, which are sent along the auditory nerve to the brain for interpretation.

5. Structure of the Human EarAQA

Sound waves travel along the ear canal and cause the eardrum to vibrate.
Vibrations from the eardrum are transmitted through three small bones called ossicles, through the semicircular canals, and into the cochlea.
The cochlea converts vibrations into electrical signals, which are sent along the auditory nerve to the brain for interpretation.

The brain interprets signals with higher frequencies as higher-pitched sounds, such as a scream.
More intense signals are interpreted by the brain as louder sounds.
The size and shape of the ear's structures determine which frequencies a person can detect.

Humans can generally hear frequencies ranging from 20 Hz to 20,000 Hz.
Different individuals may have slightly different hearing ranges, and the range typically decreases with age.
Age-related hearing loss is largely due to wear and tear of the cochlea and auditory nerve over time.