SOUND

SOUND

1. We here types of sounds coming from different sources all around us .

   • Different objects which make sounds in our everyday life include alarm clocks, television, our friends speaking, musical instruments and fireworks.

2. Sounds are produced as a result of VIBRATIONS when the medium (object which sound passes through) vibrates.

   • A good example of things which vibrates are musical instruments.

3. The DECIBEL (abbreviated dB) is the unit used to measure the intensity of a sound.

   • The decibel scale is a little odd because the human ear is incredibly sensitive.
     • Your ears can hear everything from your fingertips brushing lightly your skin to a lud jet engine.
       • In terms of power the sound the sound of the jet engine is about 1,000,000,000,000 times more powerful than the smallest audible sound.

4. On the decibel scale the smallest audible sound (near total silence) is 0dB.

   • A sound 10 times more powerful is 10dB.
     • A sound 100 times more powerful than near total is 20dB.
       • A sound 1,000 times more powerful than than near total silence is 30dB.