Noise pollution 26. ASSESS the sound level at your school . ➔ In a group, measure the sound level in your cl assroom during a lesson , writing down the ma ximum and minimum levels . You can use a sound meter or download an app to measure the sound level with your mobile phone. ➔ Write a list of possible measures to reduce noise at your school . In groups of four, discuss your proposals and make a new list that includes the measures that you f ind more effective. ➔ Make some posters of your measurements and hang them in the halls and classrooms to raise the awareness among other students at your school . Excessive sound and noise around us is called noise pollution , and it can be ver y annoy ing and even bad for our health. According to the WHO ( World Health Organisation), a level of more than 65 dB around us is dangerous for our physical and mental health . However, more than 130 million people are exposed to this level of noise ever y day. Levels of sound and noise up to 80 dB can cause listener fatigue, stress , insomnia , ir r itabilit y and aggressiveness . The r isk increases above 90 dB. This level can cause ir reparable damage, such as par tial or complete loss of hear ing. An isolated noise of over 160 dB ( like an explosion or a gunshot) can cause a per forated eardr um or other ir reversible injur ies . Our behav iour is key to reducing noise pollution , as we all are par tly responsible for the levels of sound and noise in our sur roundings . Silence 27. LISTEN to the Allegro f rom Symphony No. 2 by Anton Bruckner. Can you imagine how this piece of music would sound without rests? What is the importance of silence in our everyday life? 28. COMPLETE this melody with only rests in your notebook. Then perform it . 44 & œJ œ œ œ œ œ œ œ œ j œ œ œ œ œ Silence helps us to memor ise, learn and , in general , it has ver y positive effects on us and our sur roundings . Without silence, music can' t exist , as music is the result of the combination of sound and silence. The recommended limit in classrooms is 35 dB, but in reality the levels of noise in primar y and secondar y schools of ten reach 80 dB. A long time ago, a philosopher called Pythagoras said: ‘A fool is known by his speech, a wise man by his silence.’ 20 I Rhythm in our blood
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