Why musical instruments have characteristic sounds A Sound Idea Why musical instruments have characteristic sounds

Waves - their properties wavelength frequency speed shape type (longitudinal or transverse) polarity (if transverse)

Wavelength, Frequency & Speed Speed = Wavelength x Frequency If wave crests are 3 metres apart and the wave is travelling 12 metres every second, then 4 wave crests will pass every second. wavelength = 3 metres wave speed = 12 metres per second frequency = 4 hertz

Wave types - Longitudinal &Transverse Longitudinal - e.g. Sound Transverse - e.g. Sea, Light Wave motion is in the same direction as the wave is travelling Wave motion is at right angles to the direction in which the wave is travelling

Wave Shapes - Sine, Sawtooth & Square All waveshapes can be created by adding together a series of sine waves whose wavelengths are exact fractions of the fundamental wavelength which means their frequencies are exact multiples of the fundamental frequency

Waves - Combining Sine Waves 1

Waves - Combining Sine Waves 2

Waves - Combining Sine Waves 3

Waves - Combining Sine Waves 4

Waves - The Violin String Various modes of vibration Each end cannot move Any wavelength such that an exact number of half waves = the length of the violin string is possible

Waves - The Clarinet Various modes of vibration The air at the reed end cannot move The air at the bell end can move Any wavelength such that an odd number of quarter waves = the length of the clarinet is possible

Waves - The Real Violin

Waves - The Real Clarinet

Waves - The Numbers An Octave is a doubling of frequency = a halving of wavelength A Fifth is an increase in frequency of 50% = a reduction of wavelength by 33% A Third is an increase in frequency of 25% = a reduction of wavelength by 20%

... and now it's time to WAVE goodbye!