Put up your left hand and touch your ear. This ear flap is just the very outside of your ear. Its scientific name is the pinna. Its shape helps it to funnel sound vibrations from the air, down the ear canal to your ear drum. Just like the skin of the drum in The Homemade Orchestra, your ear drum can vibrate. Of course your ear drum is not hit with a stick! It vibrates when sound vibrations reach it down the ear canal.
The ear drum passes the vibrations to the middle part of your ear. Here you will find three of the tiniest bones in your whole body. They are so small that they could fit onto your finger tip. The hammer, anvil and stirrup make the vibrations bigger. They pass the vibrations to the oval window.
The oval window is a very thin piece of skin that passes the vibrations to your cochlea in your inner ear. The cochlea is shaped like a spiral and contains liquid. The inside of the cochlea is covered with tiny hairs. When the oval window makes the liquid vibrate, the hairs also vibrate. These hairs aren’t like the hairs on your head. They are special hairs that can change the vibrations into signals. These signals zoom along nerves and into your brain. Your brain then carries out the clever part and works out what the sound is!
Adapted from http://en.wikipedia.org/wiki/File:Anatomy_of_the_Human_Ear.svg (small print)
Click this useful link for an animation about how we hear: http://www.bbc.co.uk/science/humanbody/body/factfiles/hearing/hearing_animation.shtml
And download this great activity sheet to explore more about your ears and how you hear: