What is noise? Any unpleasant sound is noise. It's something we don't like. It's something that makes us cover our cars – the wail of a fire engine, a clap of thunder, the screech of a car's tyres when the brakes are put on suddenly.
How much sound is too much? What level docs sound become noise? Well today sound can be measured scientifically. The level of sound is measured in decibels. A decibel meter is used to register sound. Zero decibel is equal to the faintest sound heard by the human ear. A decibel meter in quiet bedroom may register around 35 decibels, In a classroom it may register around 50 decibels. This level is comfortable on the ears. It is said that most people speak in a range between 45 and 75 decibels.
Noise damages ears at 85 decibels. Hearing loss can begin when the noise level goes above 100 decibels, and actual pain is felt at 140 decibels.
A doctor in West Germany, after studying the effects of noise, concluded that sounds heard by persons when they are asleep can cause danger to their hearts and blood vessels. Noise causes the blood vessels in the brain to expand. This causes pain of various kinds.
Another doctor was researching the effects of loud music by talking to players in a rock band. One of them called out, "Speak up, Doctor, we can't hear you."
The doctor discovered that all the players suffered from hearing loss and two of then were partly deaf. The noise level of the music they played ranged from 105 to 115 decibels and they played for more than eleven hours every week.Flood is a common natural disaster. Scientists have often tried to predict floods. There are a number of reasons that cause floods, including heavy rain and cloudbursts. Due to these reasons, rivers wash their banks and cover the surrounding land. Sometimes, dams break and cause disastrous floods that leads to large – scale destruction. Timely safety measures should be taken to save human life and property.