Learningweb

  Sound is produced by vibrating the objects and it is carried in all directions with the help of a medium. Sound needs a medium to travel. It cannot travel in a vacuum. We hear sound through our ears. The eardrums of our ears sense the vibrations produced by a vibrating object and send them to the brain as the stimulus. This process is called a hearing. Frequency:  The number of oscillations or vibrations per second is called the frequency of oscillation. Noise Pollution:  The presence of excessive or unwanted sound in the atmosphere is called noise pollution. Major causes of noise pollution are sounds of vehicles, explosions including the bursting of crackers, machines, loudspeakers etc. Presence of excessive noise in the surroundings may cause many health-related problems e.g., lack of sleep, hypertension and anxiety etc. Plantation on the roadside and elsewhere is the best source to reduce the noise pollution. The loudness is expressed in a unit called decibel (dB). I...