waves paper 2 Flashcards
what are longitudinal waves and example
sound waves in air- transfer sound energy
as particles in the air move form side to side- there are reigns where that particles move closely together this is called compressions, the spaces where they are more spread out are called rarefactions
oscillations are parallel to direction of energy being transferred
longitudinal waves require a medium to travel in eg air liquid or solid
what are transverse waves and example
ripples on water surface- transfer kinetic energy
In transverse waves the oscillations are perpendicular ( at a right angle) to the direction the energy is being transferred
not all transverse waver require a medium
what do waves do ?
transfer energy from one place to another
what is oscillations
waves moving up and down
in waves it is not the air, water or solid ( medium ) that travels but the waves that travel
transverse wave image
slinky shows transverse waves and imitates the ripples of water. the red dot shows a single pint which could represent water molecule, when the wave travels through the dot oscillates up an down but does not travel along the medium
longitudinal wave image
longitudinal waves traveling along the slinky represent sound waves in air and the dot represents the particles of air which are oscillating side to side but not traveling with the wave.
what are waves ?
things that transfer energy from one place to another/ between stores, without transferring any matter.
what is an amplitude
maximum point of displacement/ movement on a wave from its undisturbed position
distance between crest of the wave and undisturbed position
what is wave length ?
a wave length is a the distance from a point on a way to the equivalent point on the adjacent wave.
what is the Greek symbol for wavelength?
lambda
how to measure wave length of longitudinal waved
measure from one compression or rarefaction to the next compression or rarefaction
what is frequency and unit
number of waves passing a point each second
(Hz) hertz
1 (Hz) = 1 wave [er second
what is a period in waves and unit ?
period is the time in seconds it takes 1 wave to pass a point
period (s) = 1 divided by frequency (Hz)
what do hertz mean
1 Hz = 1 wave per second
what is wave speed
speed at which the wave moves through the medium/ speed at which energy is transferred
wave speed equation
wave speed (m/s) = frequency(Hz) x wavelength (m)
(V) = f x Lambda
cymbals timer experiment + problems
2 people stand at a decided distance away form each other, maybe 500m. one person has a timer at zero. the other claps some cymbals when the timer begins. the other person stops the timer when they hear the cymbals.
problems are that everyone has a different reaction time so the time may not be accurate. we can reduce this error by having a large number of people with timers recording theta they hear the sound. take there results, discard any anomalous and calculate the mean.
Time between the symbols clash and hearing the sound is very short making it very difficult to press timer at the correct time. reduce problem by increasing distance.
ripple tank is used to observe features of water waves- is is shallow tank of water with a vibrating bar which is connected to a power pack. when the bar vibrates it creates ripples on the water. above the tank there is a lamb and below the tank Is a sheet of white paper. when the light shines through the water it creates an image of the waves on the paper.
yo measure wave length place a ruler on the paper and measure each wavelength or 10 wavelength at once and divide by 10
to work out frequency we place a timer next to that paper and count how many waves there are passing a marked point in 10 seconds then divide that value by 10 to get frequency per 1 second.
another way to work out wave speed is to pick a wave at the start and time how long it takes to move the length of the tank the dividing distance traveled by time take
the results however may be slightly different due to measuring errors
