A world without sounds are unimaginable. Alarm, car horn, birds chirping, ocean wave, and industrial process are the example of sounds which have significantly influencing human life. According to Koo Kean Eng, Zulhisyam Salleh and Fizatul Aini Patakor (2015), sound is a form of energy that produces a sensation perceived by the sense of hearing in humans. In physics, sound is a vibration that typically propagates due to the particles collide against each other, at each collision, the next particle is moved further, through a medium of gas, liquid or solid. In contrast to light, sound propagates much slower (330 m/sec) than light (300,00 km/sec) which could be explained during a thunderstorm where a flash comes first, and a thunder comes after a few seconds. Sound can be described by its wavelength and amplitude. The wavelength determines the frequency of the sound in Hertz unit (Hz) and a sound with a frequency of 1 Hz has a wavelength of 1 second. However, the amplitude determines the loudness of the sound that is described in decibels (dB). The larger the amplitude, the louder the sound. In contrast, smaller amplitude meaning that the sound is soft. Sound could be differentiate into two types, infra (audible) and ultra (inaudible) sound. Ultrasound waves have a frequency above the normal range …show more content…
Statistic in the United States has reported cases of hearing loss accounted for 14% of occupational illness in 2007, and twenty-two million workers are exposed to potentially damaging noise each year (Centers for Disease Control and Prevention). To prevent hearing loss, many legislations specified on noise exposure were enacted around the world in order to ensure the factories comply with the regulations. Malaysia is similar. The Factories and Machinery (Noise Exposure) Regulations 1989 was enacted to prevent hearing loss, consists of 10 parts with the total of 34