SP4 Waves Flashcards
What do sea waves do
Transfer energy to the shore, when they hit the land, the energy is transferred to the land so it can wear it away
What type of waves are waves on a surface of water
Transverse particles in the water move up and down as a wave passes but the particles are not carried to shore
Looks like a wiggly line
What are ttype of waves are sound waves
Longitudinal the particles in the material which is wave is traveling move backwards and forwards as wave passes
Look like loads of dots lol
What type of waves are earthquakes and explosions
They produce seismic waves that travel through the Earth, solid rock material can be pushed and pulled (longitudinal seismic waves) or moved up and down and side to side (transverse seismic waves)
What’s wave frequency
The number of waves passing a point each second, measured in hertz (Hz)
A 1 frequency of Herts means 1 wave passing per second,
What does the frequency of waves determine for sound
The pitch
What does frequency determine for light
The colour of light
What’s the period in waves
The length of time it take one wave to pass a given point
What’s the wavelength of a wave
Is the distance from a point on one wave to the same position on the next wave and is measured in metres
What’s the amplitude of waves
The maximum distance of a point on the wave away from its rest position
Measured in metres, the greater the amplitude of sound wave, louder the sound
What’s the velocity of a wave
The speed of the wave in the direction it’s travelling
Waves travel at different speeds in different materials
How is fm radio sent?
The music is sent by variations in the frequency of radio waves
Tell me the speed of wave triangle thing
X on top
V and T on bottom
X=distance
V=speed
T=time
What triangle link wave speed to frequency
V on top (speed)
F and weird sign thing that means wavelength on bottom
F=frequency
Wavelength symbol = wavelength
at what speed does light travel at in a vacuum
300000000 m/s (300 million)
How can you measure the speed of waves
Measure the time it takes for a wave to travel between two fixed points - the speed can be calculated from the time and distance between the points
What is refraction
When a wave changed direction when entering a new medium
Where does refraction happen
At the interface (boundary) between 2 media
What is the normal line
A line at right angles to the interface
How do we see things
We see things when light reflected from them reach our eyes
Which of the following does light travel fastest
Air
Glass
Water
Air
What happens when light passes the interface
It changes speed and this change cause the direction of light to change
What does the bend of the refraction depend on
How past the light travels into the two media and the angle of the light hitting the interface
The greater the difference in speed between the two media, the more light is bent
Which direction does light bend when light slows down
Towards the normal
What are the options of thighs a wave can do when it reaches an interface
Reflect - waves bounce off
Refract - the wave passes into the new material but changes direction to they way it’s traveling
Transmit - the wave passes the the material and is not absorbed or reflected
Absorb- the wave disappears as the energy its carrying is transferred in to the material
What happens when a wave is absorbed at an interface
The wave disappears as the Energy its carrying is transferred to the material
What happens when a wave is transmitted at an interface
The wave passes through the material and is not absorbed or reflected
What’s white light
Emitted from sun and light bulbs, made of a mixture of different frequency light and different colours, the different colours In light change speed by different amounts when the travel from glass to air or air to glass
This means they are redrafted through varying angles
How can you split white light
Can be split up into by a prism into colours of the rainbow
How can sound waves reflect
They echo when reflected by a hard surface - some material absorb sound and some transmit it well
Also reflected when It goes into another material
What’s an anechoic chamber
A room designed to remove all echoes and used to test loud speakers and other audio equipment
What changes when a sound wave enters a new material
The wavelength and velocity
NOT THE FREQUENCY
How mast does s sound wave travel in air
330m/s
What frequency does a sound wave have
10kHz
What type of wave are sound waves
Longitudinal so particles in a gas or liquid vintage forward and backwards as sound passes
What happens when sound reaches a solid
Some of the energy its transferring is reflected and some is transmitted through the solid or absorbed by it
What type of wave are vibrations in s solid
Either longitudinal or transverse waves
How does a sound wave travel through air to a solid
A sound wave causes changes in pressure on the surface, this caused particles to vibrate and so the disturbance is passed from air to solid
What’s the first step to hearing s sound
Sound waves enter the ear canal
What’s the second step to hearing sounds
The eardrum is a thin membrane, sound waves make it vibrate
What’s the third step to hearing a sound
Vibrations are passed on to tiny bones with amplify the vibrations (make them bigger)
What’s the fourth step to hearing a sound
Vibrations are passed on to the liquid inside the Cochlea
What’s the fifth step to hearing a sound
Tiny hairs inside the cochlea detect these vibrations and create electrical signals called impulses
What’s the sixth step to hearing a sound
Impulses travel along neurones in the auditory nerve to reach the brain
What diameter is the cochlea
Approximately 9 mm
How does the cochlea work
It’s a coiled tube containing a liquid, it can detect different frequencies of sound reaching the ear
What range of frequencies can a human hear
20hz to 20,000hz
What’s the cochlea like
There’s a memebrane in the middle of the tube that’s thicker and stiffer at the base and thinner at the apex(end) t
It works by different frequencies of membrane (made tk of thousand of hair cells) detect vibrations
At different thicknesses, different frequencies are detected
each hair cd is connected to a neurone that send an impulse to the brain and the brain interprets the signals as different pitches of sound
What range of frequencies does the thicker base detect
Highest ones up to 20,000hz
What is the frequency range for humans
20,000hz - 20hz
What are sounds with frequencies higher than 20,000hz also known as
Ultrasound
What can hear ultrasound
Animals such as mice - use it to communicate with eachother
Dolphins and bats use it to detect object around them using ultrasound waves
How does sonar equipment use ultrasound
Sonar equipment carried on ships or submarines send waves out and they listen for echoed when waves are reflected by objects, they measure the time for the echo being send and it being returned and used distance, time , speed triangle to determine how far away objects are
Can be used to find depth of sea too
How can ultrasound be used for humans
Making images of how a foetus is devolving by a machine detecting the time between the pulse out and recurring the echo
It creates an image by only some waves are reflected by going to a new medium such as fat or bone
What is infrasound
Sounds with a frequency less than 20hz - they can not be heard by humans
What can hear infrasound
Since infrasound waves travel further than higher frequency sound waves before they become to faint to detect
Animals such as elephants can Hear them
What events can create infrasound waves
Volcanic eruptions and earthquakes
What are the vibrations called that are caused by earthquakes
Seismic waves, the energy released by an earthquake can travel through earth as longitudinal P waves and as transversal S waves
How are seismic waves detected
By seismometers
What mediums can longitudinal waves be transmitted through
Solids, liquids, gases
What mediums can transverse waves travel through
Only transmitted by solids
What’s the S wave shadow zone
Where no S waves are detected and occurs Becuase part of the interior or the earth is liquid
Also a band around Earth called the p wave shadow zone
How do some weak p waves arrive through the p wave shadow zone
Occur if waves in the liquid core has been reflected by something solid
Tell me the layers of the earth starting from the dry surface
Crust
Mantle
Outer core (liquid)
Inner core (solid)
