Sound and light Flashcards
What is a sound wave
An invisible wave that travels through using vibrations that make the air molecules move through the air to reach the ear
What do you call the space sound travels through
A medium
What medium does sound travels through quickest and why
Sound travels through solids quickest because the particles are closer together so the wave distance is shorter
Why can’t sound travel through vacuums
There is no medium for it to travel through
Are waves a matter
No waves are just a transfer of energy
What are vibrations also known as
Oscillation
The louder the sound the …
The higher the amplitude
What does a low amplitude sound have
Less energy resulting in a smaller range of movement through the air molecules
What are up and down movements in a wave called
Undulations
What is a transverse wave
In transverse waves the vibrations are at right angles to the direction of wave travel and move up and down.
Can water waves be reflected
Yes water waves can be reflected and change to a different direction
What is a crest in a wave
The highest point of a wave
What is a trough in a wave
The lowest point of the wave
What is displacement in a wave
How far a point on the wave is from the resting line
What is amplitude in a wave
The maximum displacement, meaning the displacement from the middle lime to the crest or trough
What is frequency in waves
The number of waves produced by a source each second. It is measured in Hertz (Hz)
What machine visualises sound waves
Oscilloscopes
What does pitch tell us
How shrill or deep something is. It is also measured in Hertz (Hz)
The pitch of a sound depends on
The frequency
What range of hertz can a human hear and what is it called
20-20,000 hertz and it is called the audible frequency range
What do you call a sound above 20,000 hertz
Ultrasound
What do you call a sound below 20 hertz
Infrasound
What is 1 Hertz (Hz) equal to
1 sound wave per second
What do you call the outer part of the ear
Pinna
How does the ear hear?
- Sound waves are collected by the earlobe/pinna
- The waves travel through the ear canal
- The waves make the ear drum vibrate
- The small bones (ossicles) amplify the vibrations and hit the cochlea
- The cochlea (an organ filled with fluid) turns these into electrical impulses
- The auditory nerve takes the electrical impulses to the brain
Why is the cochlea filled with fluid
Sound travels through liquids quicker
What is the name for objects that create light
Luminous sources
How do we see non luminous sources
Light waves reflect off the object and enters our eyes
What do opaque materials do
Produce shadows and do not transmit light
In a mirror you are…
The same distance behind the mirror as you are in front, you are the correct way up and inverted.
What type of lines does light travel in
Straight
What are angles used to show in a diagram of light reflected waves
The direction of light
What do you call the ray going in
Incident ray
What does a you call the ray that is reflected
The reflected ray
What does a normal line mean in a diagram of light waves
It is 90 degrees to the mirror
Is the incident ray equal in angle to the reflected ray
Yes
What are eye problems caused by
Genetics, age, dust, bright light, how eyes developed, infectious diseases and previous eye injuries
What are objects that do not give out light
Non luminous
Why does cleaning or smoothing a surface make it shinier
Shiny surfaces are smooth so they reflect light in a regular way to form a clear image, also known as speculative reflection. Rough or bumpy surface scatter light that falls on them which makes them look duller, also known as diffused reflection. (The diagram below shows a smoother surface but a rough surface would have the arrows scattering in different places)
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\ /
\ /
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Our eyes have … lenses and what do they do
Convex. These lenses focus the light and enable us to see
What is the point where the rays cross called
Focal point
What coloured part of the eye controls the light entering
Iris
What part of the eye has photo sensitive cells
Retina