Waves

Rarefaction

________- Areas of low pressure air between compressions.

Compression

________- pulse of compressed air.

Doppler affect

________: Sound waves travel in all directions from the source but if the source is moving toward you it would be higher pitch than moving away from you.

Sound

________ is a mechanical wave and is a longitudinal wave.

Frequency

________- how many waves pass by per second.

Constructive Interference

________: Crests match up with crests and troughs with troughs to increase the amplitude of the observed wave.

Loose end

________: constructive interference and non- inverted wave.

Mechanical Waves

________: Need a medium (air, water, slinky, etc)

Frequency of a sound wave

________ controls the pitch.

Wave

A propagating disturbance (transfer of energy without transfer of matter) Particles move back and forth while the wave of energy keeps moving in one direction

Longitudinal Waves

Particle motion is parallel to wave energy motion

Transverse Waves

Particle motion is perpendicular to wave energy motion

Frequency

how many waves pass by per second

Wave velocity

how far one wave can travel in a certain amount of time

period of the wave

How long it takes for one wave to pass by the roots (T)

frequency of the wave

How many waves pass by the roots per second (F)

Doppler affect

Sound waves travel in all directions from the source but if the source is moving toward you it would be higher pitch than moving away from you

Subsonic

slower than the speed of sound

Mach 1

at the speed of sound

Supersonic

faster than the speed of sound

Principal of Superposition

The amplitude of an observed wave equals the sum of the amplitudes of all overlapping waves

Constructive Interference

Crests match up with crests and troughs with troughs to increase the amplitude of the observed wave

Destructive Interference

Crests match with troughs to decrease the amplitude of the observed wave

Beats

When two waves differ slightly in frequency, they alternate between constructively and destructively interfering

Fixed End

Destructive interference and inverted wave

Loose end

constructive interference and non-inverted wave

Standing Waves

An interference pattern caused when a wave reflects and interferes with itself, only Works on lengths that are multiples of 1/2 a wavelength

Fundamental frequency

the smallest frequency a standing wave can have

Open ended instruments

Ends of possible standing waves are antinodes instead of nodes, Fundamental frequency still occurs with half a wave, Harmonic frequencies are whole number multiples of fundamental frequency (basically the same as string instruments)

Pipes Open at ONE END ONLY

Node at closed end; Antinode at open end, Fundamental frequency occurs with 1/4 of a wavelength, Only odd harmonics (ends at an antinode)