Longitudinal Wave - Vibrations move in parallel to the direction of the motion and also originate from the point of disturbance. Energy is passed between molecules leaving the first molecule in the same position i.e. newtons cradle.
Compression is a increase in the waves density.
Rarefraction is a decrease in the waves density.
Wavelength is calculated by the distance between two crests or troughs for a transverse waves and between two peak compressions for longitudinal waves.
The amplitude of a wave is its height from the origin to the peak of the wave i.e. half the height of a full wave.
Speed of sound - Metal 5000m/s
- Water 1500m/s
- Air 333m/s (350m/s??)
Frequency is defined as the number of waves to pass a point in 1 second and is measured in Hertz(Hz)
Velocity is defined as the speed at which the wave travels measured in metres per second(m/s)
Velocity = frequency x wavelength
Standing waves disturb but do not pass through the medium. violin strings vibrate with a node(minimum) at each end and an anti-node(maximum) in the middle. Note that nodes also occur in cavities such as a flute or a room. the nodes being in the walls and the anti-nodes being the middle of the room.
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