Hearing is one of the five senses (together with sight, touch, taste and smell). They connect us to the world around.

Hearing changes sound waves in the ear into tiny electrical signals that are sent to our brains.

The sound made by any object travels along as a number of shock waves of air. These are gathered by the ear, which acts like a kind of funnel and sends them to the ear drum. The ear drum is like the skin on a drum, only much more sensitive.

Inside the ear, and beyond the ear drum is a place called the middle ear. This is filled with air, and has three tiny bones in it. The bones pick up the vibration from the ear drum and make it bigger by about thirty times.

At the inner end of the middle ear is another skin. Beyond it is a tube filled with liquid. The sound waves change the pressure in the liquid which presses on nerves, which then send signals to the brain.

If we have poor hearing, it is usually something to do with the fluid inside the ear. In this case, a hearing aid is used to make the sound going into the ear loud enough to make the inner ear work.

We also sense very low sounds through our bones, so the sound we hear is a combination of ear and bone signals.