Detecting Sound

To explain how the human ear detects sound, we first have to look at the structure of the ear:

1. The outer ear is called the pinna. It funnels sound waves into the ear canal, which is part of the middle ear.

2. These soundwaves travel through the ear canal and reach the eardrum, which is part of the inner ear. This makes the eardrum vibrate. Microphones contain a diaphragm, which works in a similar way to our eardrums.

  • Three small bones in the inner ear, which are the hammer, the anvil and the stirrup

3. The three small bones pass the vibrations onto the next part of the ear, the cochlea (the snail-shaped structure).

4. The vibrations cause movement of the fluid inside the cochlea.

  • There are tiny hairs inside the cochlea which move and detect the movement of the fluid

5. The hairs in the cochlea convert the movement from sound waves to electrical signals.

6. The electrical signals are transported to the brain, up the auditory nerve.

7. In the brain, these electrical signals are interpreted as sound, which we can recognise and understand.


The loudness of sound is measured in decibels (dB)

An average conversation is usually around 60 dB

An average concert is around 115 dB

Keep in mind, that an increase of 10 decibels means that the sound is ten times louder.

Hearing Damage

A busy street is around 80 dB and that is enough to cause hearing damage, after continuous exposure.

This is why workers that are exposed to loud sounds for long periods of time should wear ear protection.