Waves And Sound Flashcards
What are sound waves caused by
Vibrating objects
What are the vibrations in a sound wave passed through a medium as
Series of compressions and rarefactions
How does a sound wave pass through a solid
By causing the particles in the solid to vibrate
What type do wave is a sound wave
A longitudinal wave
Why can’t sound travel through space
Is mostly a vacuum so there are no particles to move or vibrate
When will you hear sound
When your ear drum vibrates by the sound waves
What are the vibrations from your ear drum passes onto
Tiny bones called ossicles, through the semicircular canals and to the cochlea
What does the cochlea do to the vibrations
Turns them into electrical signals which get sent to your brain and allow you to sense the sound
What range can humans hear in
20 hertz to 20 kilohertz
What are echoes
Reflected sound waves
What happens to sound wave when they enter a different media
They will refract
In a denser material they speed up
It’s wavelength will change but it’s frequency remains the same so it’s speed mush also change
What frequency do ultrasounds have
Higher than 20000Hz
What is partial reflection
When a some of a wave is reflected off a boundary between two mediums and some is transmitted
What can you do with partial reflection and ultrasound
You can point a pulse of ultrasound at an object and wherever the boundaries are between a substance and another substance some of the ultrasound will be reflected back
The time it takes for the reflection to reach a detector can be used to measure how far away a boundary is
What happens to ultrasound though a body
It can pass straight though but when they reach a boundary between two different media some of the wave is reflected back
How does a computer produce a video image of a foetus
They process the exact timing and distribution of echoes which are reflected by the ultrasound waves passing though the body
What can ultrasound be used for
To find flaws in objects such as pipes or wood and metals
Video imaging of babies
How can ultrasound detected cracks
They will be relegated usually by the far side of the material so if there is a crack they will reflect earlier
What is echosounding
It uses high frequency sound waves ( like uktrasound) to find the depth of water they are in or to locate objects in deep water
What causes seismic waves
Earth quakes and explosions
What detect seismic waves
Seismometers
What do seismologists do
Work out the time it takes for the shock waves to reach each seismometer and note which sorts of the earth don’t receive the shock waves at all
What happens to the Path of a wave when a wave is refracted
The wave will change speed gradually and result in a curved path
Is the properties change suddenly the wave speed changed antibiotic and the oath has a Kink
What have scientists been able to do by observing how seismic waves are absorbed and refracted
Work out where the properties of the earth change dramatically
What are the 2 types of waves
P waves
S waves
What type of wave can travel through the earths core
P waves
Properties of P waves
Longitudinal
Travel through solids and liquids
Travel faster than S waves
What are the properties of S waves
They are transverse
Can’t travel through liquids and gases
Slower than P waves
