Wave Vocab
What is amplitude? Draw an example.
A wave motion's maximum displacement from equilibrium.
What is the equation for wave speed?
v = f * λ
velocity = frequency * wavelength
What types of waves are sound waves?
Longitudinal
Which harmonics can open pipes and strings generate?
ALL harmonics!
Which harmonics can closed pipes generate?
Only ODD harmonics!
What is frequency?
The number of waves that pass a given point per second
What is the relationship between frequency and period? How do you calculate one when you have the other?
Inverse. T = 1/f OR f = 1/T
Period = 1/frequency OR frequency = 1/Period
What is the speed of sound at -10 degrees celcius?
v = 331 + (0.6)(Temp)
v = 225 m/s
What is the pulsing beat frequency you hear when two tones are played at 450 Hz and 535 Hz?
85 Hz
What would be the formula comparing the length of a closed pipe instrument to the wavelength of a tone resonating at the seventh (7th) harmonic?
L = (7/4)(λ)
Length = (7/4)(wavelength)
What is a standing wave?
A wave that appears to be stationary
What are the two types of waves? What is the difference between them?
Transverse: particles vibrate perpendicular to the direction of motion.
Longitudinal: particles vibrate parallel to the direction of motion.
What causes the Doppler Effect?
A sound wave (or a receiver) in motion.
An instrument generates its second harmonic on strings that are 4 m long. What is the wavelength?
4 m
A closed pipe instrument generates its fundamental frequency at 200 Hz. What is the frequency of this instrument's next resonant tone?
f1 = (3)f2
600 Hz.
What is a wavelength? How is it measured? Draw an example.
One full wave cycle. Measured starting from a point then tracing the next up + down oscillation (aka or "crest to crest").
Changing which below property in a string (aka the medium) changes wave speed? What is the result if the property is doubled?
Amplitude, Wavelength, Frequency, Tension
Tension. If tension is doubled, the wave speed will increase.
Two sound waves have completely destructive interference - what do you hear? Draw the base waves and the resultant wave.
Nothing!
How many nodes and antinodes exist when an open pipe instrument generates resonance at its third harmonic? Draw this.
3 Nodes and 4 Antinodes.
What is the wavelength of a wave in a 3 m closed tube resonating at its third harmonic?
4 m
What is refraction? What property of a wave changes?
Refraction: the bending of a wave as it passes from one medium to another.
Wave speed changes (aka from a different medium).
Which visible color has the shortest wavelength? What does this imply about the frequency of this color?
Violet (NOT PURPLE). From v = f * λ, violet must have the highest frequency of visible colors.
Come up with 2-3 unique ways that a person could be experiencing a red shift from the Doppler Effect.
*any type of situation where the distance between sound waves is increasing"
An open pipe instrument generates its fundamental frequency tone at 600 Hz. What is the frequency heard at the fourth harmonic?
2400 Hz.
A bassoon (closed pipe instrument) generates a fundamental frequency of 60 Hz. This resonant tone has a wavelength of 4 meters. How long is the bassoon?
1 meter