Sound J.Sample 2014

Sound Sound is a form of energy produced and transmitted by vibrating matter. Sound must have a medium, (matter), to travel through. – Gasses, (air), liquids, or solids – Solids are fastest, molecules close together – Gasses are slowest, molecules farthest apart Sound cannot travel in a vacuum. – No medium to carry the waves.

Waves Sound waves are compression, (longitudinal) waves. – Molecules move backward and forward carrying the energy like a spring. – Some molecules are pressed together, compression – Some molecules are spread out, rarefaction

Frequency & Wavelength Wave length; the distance between two compressions or two rarefactions. – Measured from point to same point on two consecutive waves. Frequency is the number of wavelengths in a given unit of time. – Measured in hertz or cycles per second

Amplitude Amplitude is the amount of energy in a compression wave. – Related to intensity and volume – Loud sound many molecules with much force. – Soft sound fewer molecules with less force.

Pitch Pitch is determined by the frequency of a vibrating object. – Faster frequency, higher pitch, soprano – Lower pitch, slower frequency, bass As frequency changes so does pitch.

Sources Some animals can make and hear sounds different from those of humans. Musical instruments vibrate to produce sound. – Different instruments produce different vibrations in different ways. – Percussion; drums, symbols – Stringed; violin, piano, guitar – Wind; flute, clarinet, trumpet, trombone – Electronic; organ, keyboards, guitar

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