unit 4 test Flashcards
what are the two types of waves?
a transverse wave, and a longitudinal one.
what is a transverse wave?
a wave where particles are displaced perpendicular to the direction of the wave. we use this one the most.
what is a longitudinal wave?
a wave where particles move in the same direction of the wave motion. like a spring.
what is a crest?
the top of a wave
what is a trough?
the bottom of a wave
what is amplitude?
the distance from the middle of a wave to the crest or trough.
what is a compression?
a spot on a longitudinal wave where the coils are compressed. this is the maximum density.
what is a rarefaction?
the part of a wave where coils are spread apart. this is the point of minimum density.
what is frequency?
the amount of cycles that happen in a unit of time. measured in hertz.
what is period?
the time to complete a wave
how to measure the speed of waves?
v=f λ. measured in hertz i think. length is 1/2 λ. λ is v/f
what does loudness effect?
the amplitude. loud= large
quiet= small
what does pitch effect?
the frequency. high pitch= high frequency
low pitch = low frequency
what does quality affect?
the wave form. pure is simple, rich is complex (includes harmonies and cool waves), and noise is irregular and doesnt have a real wave look.
what is the principle of superposition?
the amplitude of two interfering waves is the sum of both waves combined
what is beat frequency?
two vibrations with similar frequencies. sound signals interfere and its heard as a separate note.
what is resonance?
two things vibrating in harmony resonate. this is like the phet simulation where that wave got really really big. like pushing a swing
what is the doppler effect?
things push their wave lengths, wavelengths in front are shorter and behind they’re longer. its used by police,weather people.
when something is coming at you what does it sound like?
the pitch is higher bc wavelengths are shorter
what is a shockwave?
happens when something moves at speed of sound. waves superimpose eachother, when you break this barrier, you get a sonic boom. this is what happens with thunder.
what is a node?
when the lines all intercept on the axis. fixed ends have nodes
what is an antinode?
when the lines are not on the axis. they are in a crest or a trough. open ends have antinodes
what happens when a wave undergoes a fixed end?
the wave is reflected and inverted along the axis.
what happens when a wave undergoes an open end>
its reflected with the same orientation as the incoming wave.
how do harmonics work.
each harmonic goes up by half a wavelength. 1st harmonic:
fixed on both ends = 1/2 λ
fixed on one end= 1/4 λ
open both ends = 1/2 λ
how does hearing go in the outer ear?
the ear collects the soundwaves and directs them into the middle ear, vibrates eardrum, a part of the middle ear.
how does hearing go in the middle ear?
the vibrartions get magnified on the eardrum, that is very much like a regular drum. bones in the middle ear magnify the vibrations as well. they are the stirrup, hammer, and anvil.
how does hearing go in the inner ear?
it goes into the cochlea, causes pressure waves that pass over tiny hairs, which converts it to little chemical signals of sounds that go from the auditory nerve into the brain.
how does echolocation work in bats, and dolphins/
they send out high frequencies that hit nearby objects and reflect back off towards the animal. sound comes from sacks by the blowhole, and gets back to the fat filled cavity in their lower jaw.
how do elephants do echolcation?
they deliver long, low frequency sounds that travel through the earth and they can feel them in their feet.
