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state the two types of waves
transverse
longitudinal
state examples of transverse waves
ripples on water surface
s-waves
electromagnetic waves
state example of longitudinal waves
sound waves travelling through air
p-waves
state the areas longitudinal waves show
rarefaction
compression
state definition of a wave
repeated vibrations
that transfer energy
state transverse wave definition
waves where points along its length
vibrate perpendicular
to the direction of energy transfer
state longitudinal wave definition
waves where points along its length
vibrate parallel
to the direction of energy transfer
state what waves transfer
energy
not particles of the medium
state peak definition
highest point of a wave
state trough definition
lowest point of a wave
state rarefaction definition
longitudinal waves that are spaced apart
state compression definition
longitudinal waves that are close together
state the differences between transverse and longitudinal waves based on structure
transverse = peaks and troughs
longitudinal = compressions and rarefactions
state the differences between transverse and longitudinal waves based on vibrations
transverse = perpendicular to direction of transfer of energy
longitudinal = parallel to direction of transfer of energy
state the differences between transverse and longitudinal waves based on vacuum
transverse = only electromagnetic waves can travel through
longitudinal = no waves can travel through
state the differences between transverse and longitudinal waves based on material
transverse = can move in solids, liquids and gases
longitudinal = cannot travel in a vacuum
state the differences between transverse and longitudinal waves based on density
transverse = constant density
longitudinal = changes in density
state the differences between transverse and longitudinal waves based on pressure
transverse = constant pressure
longitudinal = changes in pressure
state the differences between transverse and longitudinal waves based on speed of wave
transverse = dependent on material it’s travelling in
longitudinal = dependent on material it’s travelling in
state amplitude definition
distance from the undisturbed position
to the peak of trough
of a wave
state the symbol and unit of amplitude
symbol = A
unit = m
state wavelength definition
distance from one point
to the same point
on the next wave
state how to measure wavelength in transverse waves
measured from one peak
to the next peak
state how to measure wavelength in longitudinal waves
measured from centre of one compression
to the centre of the next compression
state the symbol and unit for wavelength
symbol = λ
unit = m
state frequency definition
number of waves
passing a point
in a second
state the symbol and unit of frequency
symbol = f
unit = Hz
state time period definition
time taken
for one full cycle
of a wave
state symbol and unit of time period
symbol = T
unit = s
state equation to calculate time period
T (s) = 1 / f (Hz)
state wave speed definition
speed at which
energy is transferred
through the medium
state equation to calculate wave speed
v (m/s) = f (Hz) x λ (m)
describe a method to measure the speed of sound waves in air
two people stand 100m apart
distance between them is measured using a trundle wheel
one person has two wooden blocks, which they bang above their head
the other person starts the stopwatch when they see the person bang the wooden blocks together
the other person stops the stopwatch when they hear the sound
the experiment is repeated multiple times to calculate an average speed
use equation speed = distance / time to calculate the speed of sound
state the variables in measuring wave properties
independent = frequency
dependent = wavelength
control = same depth of water
state the method to measure the speed of ripples on a water surface
set up a ripple tank with a screen and ruler beneath, a light source above and a wooden bar supported by elastic bands in the water
fill the ripple tank with a water depth of no more than 1cm
turn on the power supply and light source to produce a wave pattern on the screen
wavelength of the waves is determined by using the ruler to measure the length of the screen and dividing the distance by the number of wavefronts
frequency can be determined by timing how long it takes for a given number of waves to pass a particular point and dividing the number of wavefronts by the time taken
record the frequency and wavelength in a table and repeat measurements
use the equation v = λ x f to calculate wavespeed
state what increases the rate of energy transfer by waves
more molecules present in the medium
explain what happens in the refraction of sound from a less dense medium to a denser medium
wavelength increases
frequency stays the same
velocity increases
explain what happens in the refraction of sound from a denser medium to a less dense medium
wavelength decreases
frequency stays the same
velocity decreases
explain how the speed of sound in air is affected by temperature
increased temperature increases the speed of sound waves
as air molecules have gained kinetic energy
thus making them move faster
allowing them to carry sound waves faster
state the variables investigating reflection and refraction
independent = angle of incidence
dependent = angle of reflection
control = distance of ray box from mirror
stated method of the investigation of reflection and refraction
set up a piece of paper and a ray box at 45 degrees to a plain mirror
use a ruler to mark a 10cm straight line in the middle of the paper
use a protractor to draw a 90 degree line that bisects the 10cm line
place the mirror on the line
switch on the ray box and aim a beam of light at the point of bisection
use a pencil to mark a point where the light beam leaves the ray box and a point on the reflected beam about 10cm away from the mirror
remove the ray box and mirror
use a ruler to join the two marked points to the point of bisection
use the protractor to measure two angles from the 90 degree line
the angle for the ray towards the mirror is the angle of incidence and the other angle is the angle of reflection
repeat the experiment three times with the beam of light aimed at different angles
analyse the investigation of reflection and refraction
law of reflection states: angle of incidence = angle of reflection
if the experiment was carried out correctly, angle i and angle r should be the same
state the variables in the investigation of the refraction of light by a perspex block
independent = angle of incidence
dependent = angle of refraction
control = use the same perspex block
state method of the investigation of the refraction of light by a perspex block
place the perspex block on a sheet of paper and carefully draw around the block using pencil
switch on the ray box and direct a beam of light at the side face of the block
mark on the paper: a point on the ray close to the box, point where the ray enters the block, point where the ray exits the block and a point on the exit ray 5cm away from the block
draw a dashed line normal to the outline of the block where the points are
remove the block and join the points marked with three straight lines
replace the block within the outlines and repeat the experiment with the ray box pointed at the block from different angles
record these results in a table
state what happens when sound waves travel through solids
vibrations in the solid
state what happens when sound waves travel through the ear
the ear drum and other parts of the ear vibrate
causing the sensation of sound
state what restricts the limits of human hearing
conversion of sound waves to vibrations of solids
works over a limited frequency range
explain the effect of sound waves on the ear drum
eardrum is made of skin and tissue
sound waves travel down the auditory canal towards the eardrum
pressure variations created by sound waves exerts a varying force on the eardrum
causing it to vibrate
vibration pattern of sound creates the same pattern of vibration in the eardrum
explain how the ear converts sound waves into sound
sound waves travel down the auditory canal towards the eardrum
pressure variations created by sound waves exerts a varying force on the eardrum
causing it to vibrate
vibration pattern of sound creates the same pattern of vibration in the eardrum
the eardrum vibration is transferred to three small bones
the vibration of the small bones then transfers to vibrations in the inner ear
nerve cells in the inner ear detect sound and send a message to the brain
giving the sensation of sound
state the human range of hearing
20 Hz - 20,000 Hz
state examples of the use of sound waves to explore structure
echo sound - helps ships detect the ocean floor
ultrasound - used to look inside the human body and crack detection
reflection seismology - detects oil and gas underground
seismic activity - used to investigate earth’s structure
state what properties of a substance allow for detection of hidden structures
reflection
absorption
transmission
speed of sound in the substance
explain how the properties of a substance allow for detection of hidden structures
each type of substance will produce different amounts of reflection, absorption and transmission
each type of substance will also transmit sound at a different speed
certain structures will reflect a proportion of the sound wave and transmit the rest
some substances will absorb sound waves with little reflection
by detecting the amount of sound reflected and the speed of the wave
the hidden structure can be identified
state the frequency of ultrasound waves in relation to the human hearing range
ultrasound waves have a higher frequency
than the upper limit of human hearing
state where ultrasound waves are partially reflected
at the boundary between two different medias
state how to determine how far a boundary that causes ultrasound waves to be partially reflected is
time taken for the reflections
to reach the detector
state what ultrasound waves are used for
industrial imaging
medical imaging
state what produces seismic waves
earthquakes
state what type of wave p-waves are
longitudinal
seismic waves
state how p-waves travel through solids and liquids
at different speeds
state what type of waves s-waves are
transverse
seismic waves
state whether s-waves can travel through liquids
no
state what seismic waves provide evidence for
p-waves and s-waves
help to explore
the structure and size
of earth’s core
explain what echo sounding is used to detect and measure
detects objects in deep water
measures water depth
state what echo sounding uses to detect and measure objects in water and water depth
high frequency sound waves
state what the study of seismic waves has provided
new evidence
that led to discoveries
about parts of earth
that aren’t directly observable
state what electromagnetic waves are
transverse waves
that transfer energy
from the source
to an absorber
state what electromagnetic waves form
continuous spectrum
state whether electromagnetic waves travel at the same velocity through air and vacuums
yes
state how the electromagnetic spectrum is grouped
by wavelength and frequency
state the electromagnetic spectrum from longest wavelength to shortest wavelength
radio waves
microwaves
infrared
visible light
ultraviolet
x-rays
gamma rays
state the electromagnetic spectrum from lowest frequency to highest frequency
radio waves
microwaves
infrared
visible light
ultraviolet
x-rays
gamma rays
state what electromagnetic waves human eyes detect
visible light
describe the energy transfers by microwaves
water molecules absorb certain wavelengths of microwave radiation
causing microwave ovens to transfer energy by radiation
to the thermal store of the food placed inside it
describe the energy transfers by infrared
all hot objects emit infrared radiation
these emitted waves can then be absorbed by other objects
transferring energy to the thermal store of these objects and the surroundings
by radiation
describe energy transfers from the sun
the sun emits several types of EM radiation including
visible light waves which allow living creatures to see
infrared waves which heat up the earth
ultraviolet waves which cause suntans and sunburns
energy is transferred from the sun by radiation
state how the wavelength of EM radiation affects substances
affects if the substances
absorbs, transmits, refracts or reflects
EM waves
describe how EM waves affect the refraction of a substance
the different velocity the EM waves travel through different substance
causes differences in the refraction of substances
state when refraction occurs
when light passes a boundary
between two transparent mediums
state what happens in refraction
light rays undergo a change in direction
state what the normal is
hypothetical line
perpendicular to the surface of the medium
state the change in direction of a light ray from a less dense medium to a denser medium
light ray bends TOWARDS the normal
explain the change in direction of a light ray from a less dense medium to a denser medium
velocity of light rays DECREASES
causing the light ray to bend
towards the normal
state the change in direction of a light ray from a denser medium to a less dense medium
light ray bends AWAY from the normal
explain the change in direction of a light ray from a denser medium to a less dense medium
velocity of light rays INCREASES
causing the light ray to bend
away from the normal
state the change in direction of a light ray when passing along the normal
light ray DOES NOT BEND
state the wave properties that change during refraction
velocity
wavelength
state what the different frequencies of visible light account for
different colours of light
state what happens when light refracts
it doesn’t change colour
explain why the refraction of light doesn’t cause a change in wave frequency
different frequencies of visible light are cause by changes in colour
when light refracts it doesn’t change colour
meaning refraction causes the frequency of the visible light wave to remain the SAME
state the method to draw a ray diagram
draw a 2D prism on a piece of paper
draw a parallel ray on the left of the prism
draw the refracted ray at the first surface
the ray will bend towards the normal as the prism is denser than air
draw the refracted ray at the second surface
the ray will bend away from the normal as the air is less dense than the prism
explain how to use wave front diagrams to explain refraction
when waves hit different mediums
different parts of the wave enter the medium at different times
leading to a change in wavespeed
difference in speed between parts of the wave in the first and second medium causes the wave to bend
leading to a change in direction
this refraction is represented in wave front diagrams
state the variables in the investigation of infrared radiation
independent = colour
dependent = temperature
control = same volume of water
state the method of investigating infrared radiation
set up four identical flasks painted black, grey, white and silver
fill the flasks with hot water, ensuring the measurements start from the same initial temperature
note the starting temperature
use a stopwatch to measure the temperature every 30 seconds for 10 minutes
analyse the investigation of infrared radiation
all warm objects emit thermal radiation in the form of infrared waves
intensity of the emitted radiation depends on
temperature, surface area and colour of the object
most of the heat lost from the flasks is due to conduction and convection, which will be the same for each flask
any difference in heat lost between flasks must be due to infrared radiation
plot a graph of temperature (y-axis) against time (x-axis) to compare heat loss in each flask
state what produces radio waves
oscillations
in electrical circuits
state what absorbed radio waves may create
alternating current
at the same frequency
as the radio wave
state what radio waves can induce
oscillations
in an electrical circuit
state what changes in atoms and the nuclei of atoms causes
the generation of EM waves
the absorption of EM waves over a wide frequency range
state what gamma rays originate from
changes
in the nucleus
of an atom
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