MOD - 14

 Sound waves

mechanical waves that require a medium to travel through. (air, water)

longitudinal

waves in which the displacement of the medium is parallel to the direction of wave propagation. ( sound wave)

 rarefaction

troughs of a longitudinal wave where the medium is less dense than in the surrounding areas.

compression

crests of a longitudinal wave where the medium is denser than in the surrounding areas.

measure the wavelength of a longitudinal wave

The distance between two successive compressions or rarefactions in a longitudinal wave.

Pitch

The perceived frequency of a sound, which determines how high or low the sound seems to a listener.

infrasonic

Sounds with a frequency below the range of human hearing, typically below 20 Hz.

ultrasonic

Sounds with a frequency above the range of human hearing, typically above 20,000 kHz.

 Sound intensity is an inverse square law

states that the intensity of sound decreases proportionally to the square of the distance from the source. This means that as you move away from the sound source, the perceived loudness decreases rapidly. (Double the distance = ¼ intensity, triple is 1/9 intensity, Cut distance in half  = 4x intensity)

Doppler effect

is the change in frequency or wavelength of a wave in relation to an observer moving relative to the wave source. It is often heard as a change in pitch of a sound as the source moves closer or farther away.

What is creating the vibrations in tuba

players lips

What is creating the vibrations in clarinet

the reed in the mouthpiece

What is creating the vibrations in drum

the drumhead being struck

What is creating the vibrations in violin

the strings being bowed or plucked

resonance

the occurrence of a vibrating object causing another object to vibrate a higher amplitude.

Node

A point along a standing wave where the wave has minimal or no amplitude/motion

Antinode

A point along a standing wave where the wave has maximum amplitude and motion.

Open tube

node has to be in the middle due to fundamental frequency and the two antinodes are at the end

Closed tube

closed at one end therefore making it a node, open end is the antinode. (¼ wavelength is the smallest possible)

Timber

mix of two unique harmonies