Rattling trucks, roaring jets, squeaking chalk, and creaking doors don’t make music. They make sounds that disturb us - sounds we don’t want to hear. These unwanted sounds are called noise.
Noise is hard to stop. Like other sounds, noise travels through air and through solid things - even through walls.
But some materials actually soak up noise. They absorb sound waves and keep them from travelling. Inside a building, rugs and curtains soak up sound. The soft threads and tiny air spaces in the material help trap the vibrations. Special ceiling tiles can trap sound vibrations, too. The tiles are full of tiny holes, like a sponge. When sound waves strike the tiles, they bounce around inside the holes until they get weaker and die away.
People who work with aeroplanes and other heavy machines wear special helmets and earmuffs to cover their ears while they are working. The sound-absorbing material shuts out most of the noise that could bother them or even hurt their ears.
There is a special branch of science that deals with the way sound affects people. This science is known as acoustics. Acoustics helps people design theatres so that music sounds good. It also helps them work out how to control harmful noise. Scientists even use acoustics to study how we make and understand sounds.
Picture Credit : Google