P5 - waves in matter Flashcards
what do waves do?
transfer energy in the direction they’re travelling
what happens when waves travel through a medium?
the particles of the medium vibrate and transfer energy between each other; overall the particles stay in the same lattice but energy is transferred
what is the amplitude of a wave?
the displacement from the rest position to a crest or trough
what is the wavelength of a wave?
the length of a full-cycle of the wave e.g. from crest to crest or compression to compression
what is the frequency?
the number of complete waves or cycles passing a certain point per second
what is the period of a wave?
the number of seconds it takes for one full cycle; period = 1/frequency
what type of vibrations do transverse waves have?
sideways
describe transverse waves
in transverse waves, the vibrations are perpendicular to the direction the wave travels
what are some examples of transverse waves?
- all electromagnetic waves
- S waves
- ripples/waves in water
can transverse waves travel through liquids?
they can travel on the surface of a liquid, but they can’t travel through liquids
what type of vibrations do longitudinal waves have?
parallel
describe longitudinal waves
in longitudinal waves, the vibrations are parallel to the direction the wave travels
what are some examples of longitudinal waves?
- sound waves
- P waves
what do longitudinal waves do to the arrangement of the particles in the medium they pass through?
longitudinal waves squash up and stretch out the arrangement of particles in the medium they pass through, making compressions and rarefactions
what is the equation for wave speed?
wave speed = frequency x wavelength
what are the units for frequency?
Hz
what can you use to measure the speed of sound?
an oscilloscope
when experimenting with an oscilloscope, what can be used to generate sounds with a specific frequency?
by attaching a signal generator to a speaker, you can generate sounds with a specific frequency
when experimenting with an oscilloscope, what can be used to find the wavelength of the sound waves generated?
you can use two microphones and an oscilloscope to find the wavelength of the sound waves generated
how is an oscilloscope used to measure the speed of sound?
- set up the oscilloscope so the detected waves at each microphone are shown as separate waves
- start with both microphones next to the speaker, then slowly move one away until the two waves are aligned on the display but have moved exactly one wavelength apart
- measure distance between microphones to find wavelength
- use formula to find speed of sound waves passing through the air (frequency is whatever you set signal generator to in the first place)
what can you measure using a ripple tank?
- speed
- frequency
- wavelength
what is used to generate waves in a ripple tank?
a signal generator attached to a dipper
how does the signal generator attached to a dipper generate waves in a ripple tank?
the signal generator moves the dipper up and down to create water waves at a fixed frequency
to measure frequency with a ripple tank, what is needed?
a cork and a stopwatch