WHAT IS NOISE?

1. No exact definition of "noise" can be given. Because whether we experience sounds as a disturbance or not depends on many things. It is, for example, important to know whether we ourselves cause the noise or whether we have to endure it; whether the noise can be avoided or whether it is unavoidable; whether we are tired or fit. Visitors at a fun-fair enjoy the racket, but people who live close to the fun-fair feel disturbed about it. Passengers in jet-planes accept the din during take-off, but people living close to the airport are disturbed.

2. How strong a noise is and how many sound vibrations there are, is nowa-days internationally expressed in decibels. When you whisper or when leaves rustle there is 10 to 20 decibels. During a normal conversation the noise produced may be about 50 decibels; in crowded streets about 75 or 80 decibels.

3. Our hearing can already be injured when we are exposed to about 85 decibels for a longer period. A group of pop - musicians produce round about 120 decibels and 140 to 160 decibels are produced at the lake-off of a large jumbo-jet plane.

4. During tests on animals it has been proved that noise can be fatal. The Chinese used to torture criminals with noise producing instruments until they dropped dead. Also recently noise has killed human beings directly, damaged buildings, shattered windowpanes, e.g. when a jet passes the sound-barrier.

5.With increasing traffic and expanding industrialization the strain on our ears will certainly increase, too. 1 his will lead to occupational diseases in certain trades, to hardness of hearing, to sleeplessness and such complaints. Therefore we must do everything in our power to protect ourselves against noise.

7. Прочтите 5-й абзац текста и вопрос к нему. Из приведенных вариантов ответа укажите номер предложения, содержащего правильный ответ на поставленный вопрос:

Much noise leads to occupational diseases in certain trades. What must we do?

1. insulation of walls

2. to turn radio and TV low.

                 3. do everything to protect ourselves against noise.