The wave equation Flashcards
what is a wave?
a wave is a transfer of energy
what is a medium?
a medium is a substance that can ‘carry’ the wave, for example a solid, liquid or gas
what happens when a wave travels through a medium?
the particles in the medium might move but they don’t travel with energy
wavelength
the distance between two identical points on a wave
what is wavelength measured in?
metres
what is the symbol for wave length?
λ
frequency
how many wavelengths there are per second (number of complete waves per second)
does frequency have to be a whole number?
no it does not
what is frequency measured in?
Hertz (Hz)
amplitude
the maximum displacement of a point on a wave from its equilibrium position (how tall a wave is)
what is amplitude measured in?
metres
period
the time taken for one full wavelength (how long it takes for one wave to go through a certain point)
what is period measured in?
seconds
time period
the time taken for 1 whole wave to pass through a fixed point
wave speed
the distance a wave travels in one second
how do you use a ripple tanks to measure the frequency of water waves?
count the number of waves past a point and measure how long this takes
what was the independent variable in the ripple tank PAG?
frequency
what was the dependent variable in the ripple tank PAG?
wavelength
what were the control variables in the ripple tank PAG?
the amount of water
what was the method for the ripple tank PAG?
- place a ruler in the ripple tank
- measure the distance between wave peaks, this is the wavelength
- count how many waves pass a point in 10 seconds, this is the frequency x 10
- calculate the wave speed
- repeat for different wave frequencies
do you expect the speed of the waves to be the same every time in the ripple tank PAG?
No, because we change the wavespeed
why would this practical be different without slow motion?
yes, because it is very hard to measure wavelength and number of waves
how would a stroboscope improve the ripple tank PAG?
it produces a flashing light with the same frequency as the waves, the waves appear stationary on the screen and that allows us to measure the wavelength accurately
what are two possible sources of error in the ripple tank PAG?
- couldn’t count number of waves accurately
- couldn’t measure wavelength accurately
what are two ways to improve the ripple tank PAG?
- take a slow mo video in order to calculate the frequency
- take a picture/use a stroboscope
