In the air, sound waves travel at a speed of 340 metres per second, but they travel at almost 1,500 metres per second in water. This is why dolphins and whales can communicate with each other at distances of up to 30 kilometres. Sound When an object v ibrates , it emits sound waves that travel through the air, water or another medium until they reach our ears . The sound wave of a long sound v ibrates for longer than the sound wave of a shor t sound . long sound short sound The sound wave of a high sound v ibrates more quick ly than the sound wave of a low sound . high sound low sound The sound wave of a loud sound has taller waves than the sound wave of a quiet sound . loud sound quiet sound 20. LOOK at the change in this sound wave and choose the right answer. From a scientific point of v iew, sound waves are responsible for the difference of sound and noise. The sound waves of music are regular and organised , and they feel pleasant , while the sound waves of noise are ir regular and disorganised , and they feel unpleasant . sound noise At f irst it's high and then it gets lower. No! It starts forte and ends piano. 1 2 16 I Rhythm in our blood
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