How do we hear?

Detecting Sound

Your ear is an amazing organ, millions of years of evolution has developed it into what you see today.

The ear is made up of 3 parts, the outer ear, middle ear and inner ear.

Your ear detects sound waves. The outer part of your ear is called the Pinna. It directs sound waves into your auditory canal.

The auditory canal leads to the ear drum. These 3 parts of the ear, create the Outer ear.

As the ear drum vibrates, it sends the vibrations to the ossicles. The ossicles are tiny bones, that amplify the sound. They make up the middle ear.

The vibrations continue onto the liquid in the cochlea. Thousands of tiny hairs move with the vibrations. Specialised cells read this hair movement, and turn it into electrical signals.

The signals travel down the auditory nerve to the brain.

These make up the inner ear.

Sound intensity is measured in decibels (dB).

As the dB scale increases by 10, the sound intensity is multiplied by 10.

A dB of 40 is 100 times more intense than a 20 dB sound.

We normally speak at around 60dB. A jet taking off is 100dB, and a gun shot is 140dB.

Your ear is a very sensitive piece of equipment, making a hole in the eardrum can impair your ability to hear. However the ear drum can repair itself.

Ear wax can cause damage to your hearing.

Loud sounds or head injuries can permanently damage your hearing.

Questions

Short Answer Questions

1. Copy and Complete the sentence bellow

When a sound wave enters you ear it makes the __________ vibrate. This makes the ________ vibrate. The ________ vibrates and this makes the liquid inside your ________ vibrate. Cells at the base of _______ inside your _______ produce an electrical signal that travels up your _________ to your brain. Sound intensity is measured in _________ . Your hearing can be ______________ by loud sounds. In a microphone a ____________ vibrates, which produces an electrical signal.

2. Explain how your ear can be permanently damaged

3. Explain how your ear can be temporarily damaged.

4. Create a poster, with a diagram of the ear in the centre. Label it and explain the steps involved with us hearing sounds.