Waves Flashcards
What do waves transfer/not transfer?
energy and information
not matter
(e.g. a water wave moves but a ball in the water doesn’t)
What can waves be described as?
an oscillation or vibration around a rest/fixed position
oscillation/vibration
repeated movement back and forth about a fixed point
Name 5 properties that waves have
frequency
speed
wavelength and amplitude
(time) period
frequency
number of waves passing a point per second
hertz (Hz)
speed
how fast a wave moves
m/s
wavelength
distance covered by a full cycle of the wave
distance between peak-peak or trough-trough of a wave
amplitude
maximum displacement of a wave from its rest position
distance between the middle of the wave and the peaks/troughs
(time) period
time taken for a full cycle of the wave
1/frequency
measured peak-peak or trough-trough
rest position
undisturbed position of particles when they are not vibrating
displacement
distance that a certain point in the medium has moved from its rest position
peak
highest point above the rest position
or
number of waves passing a point each second
trough
lowest point below the rest position
longitudinal waves
a wave that moves in the same direction as the direction in which the particles are vibrating
transverse waves
a wave that moves in a direction at right angles to the way in which the particles are vibrating
direction of oscillations in longitudinal waves vs transverse waves
parallel to the direction of wave travel
right angles to the direction of wave travel
2 examples of longitudinal waves
sound waves
seismic P waves
(particles in the material the sound is travelling through move back and forth in the same direction the sound is travelling)
3 examples of transverse waves
water surface
electromagnetic waves (light)
seismic S waves
medium
a material through which a wave can be transmitted
mechanical waves
cause oscillations in a solid, liquid, or gas, and must have a medium to travel through
once the wave has passed the medium ends up where it started
can be longitudinal or transverse
electromagnetic waves
cause oscillations in electrical and magnetic fields
are all transverse
Give two ways in which longitudinal and transverse waves are
a) similar
b) different
a) both transfer energy without transferring matter
both have an amplitude, speed, wavelength, and frequency
b) particles in longitudinal waves vibrate along the direction of movement
particles in transverse waves move at 90 degrees to the direction of travel
they can have different speeds, frequencies and wavelengths
a) Sketch a transverse wave and mark the amplitude and wavelength on it
b) Draw an arrow to show which way the wave moves
c) Draw a small particle on the wave, with arrows to show which way it moves
a) amplitude is the distance of a peak/trough from the rest position
wavelength is the distance between peaks/troughs
b)
c) particles move up and down
A graph shows a wave. Each square represents 1mm.
The wave rises 4 squares before falling again.
Work out the amplitude of the wave.
middle = 4/2 = 2
2 mm
compression
an area of increased pressure
the particles in a wave are closer together than average
rarefaction
an area of reduced pressure
the particles in a wave are further apart than average
On a wave graph of a longitudinal wave, what do the peaks and troughs also represent?
peaks: compression
troughs: rarefaction
