By Royal Society University Research Fellow Dr Walter Marcotti
University of Sheffield
What is Sound?
Sound is a vibration that travels through air, liquids and solids like waves across the ocean. Sound travels through air at about 760 miles per hour. It travels faster and more effectively in water, which allows whales to sing to each other over thousands of miles, and faster again through solid materials like railway tracks.
How do we hear?
The sound of a name travels inside the ears to a coiled structure called the cochlea, where sensory cells detect incoming vibrations. The cells convert these vibrations into a pattern of tiny electrical signals that the brain perceives as loudness, pitch and a host of other features that enable it to reconstruct the name and to place it amongst all the memories associated with that name. More of the brain is devoted to hearing than to any other sensory system.
Why do we need to hear?
Language is a defining feature of human culture and the ear is best adapted to receiving human speech. We use the complex, asymmetric shapes and locations of our two outer ears to create 3D maps of the soundscape around us and we integrate this with our other senses to provide information about the external world.
Why do we enjoying listen to certain sounds (like music)?
Sounds can sooth or cause excruciating pain. They are deeply associated with emotional experience and from childhood they form part of our long term memories. The pleasures of particular sounds are part of the mystery of the chemistry of the brain.