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SOUND - Coggle Diagram

- - - - percussion instruments => they are played by striking them and this produces vibrations
        
        As the instrument vibrates, the air nearby vibrates and the vibrations travel through the air to the audience's ears.
        
        Sounds travel through the air as vibrations. These can travel through any material.
- - - - Usually, this is far too short a time for us to notice.
        
        However, there are occasions when we may notice the time it takes for the sound to travel (when we hear an echo after we shout or when we see a flash of lightning before we hear the roll of thunder).
        
        Sound travels faster through solids then through gases and its speed changes if the temperature of the air changes.
        
        How to measure the speed of sound
        
        "time-of-flight" method => Two wooden blocks and to microphones are arranged in a straight line. The bang from the block is picked up first by mic 1 and then by mic 2. The first activates a timer and the second stops it.
        
        sound of speed = distance between the microphones / time taken by the sound to travel between them
      - distance(m) / 330 m/s
- - - - up-and-down pattern of vibrations
        
        pure notes => the ones produced by a signal generator, which have a very simple shape
        
        We can measure:
        
        period (T) => number of seconds for one vibration
        
        frequency (f) (Hz) => number of vibrations per second
        
        f = 1/T
        
        1 more item...
- - - - As an object vibrates, air molecules are pushed back and forth. The vibrations travel through the air to our ears.
        
        Sound cannot travel through a vacuum because there are no molecules to vibrate back and forth.
    - - a smoothly varying up-and-down line
        
        There is an alternation of compressions (areas of the sound waves where the air molecules are close together) and rarefactions (areas in which the air molecules are less closely packed together)