SOUNDS and liiiiigggghhhhht Flashcards
What is light?
The transfer of energy
What is the normal?
A 90 degree line to a surface
How do we see?
When light reflects of an object to our eyes.
What are luminous objects?
Sources of light, like the Sun.
What does light require to go?
Nothing; it can pass through any or even no medium.
What is the angle of incidence?
The angle between the normal and a light ray.
What is the angle of reflection?
The angle between the normal and a reflected light ray.
What is the angle of refraction?
The angle between the normal and a refracted ray.
What does light do if it passes through the boundaries of mediums?
It bends either away or towards the normal depending on whether light goes faster or slower through the new medium.
What is the critical angle and what is it approximately?
It is the angle at which a light will perfectly reflect of a surface. It is around 42 degrees.
What are the 3 primary colours of light?
Red, blue and green.
How do we get all the other colours on the spectrum?
By mixing different amounts of red, green and blue light.
What is white and black light?
White light is a mix of all the colours and black light is no colours.
If a blue object had red light shone on it, what colour would it be and why?
Black because blue objects only reflect blue light and absorbs the other colours of the spectrum.
How does a filter work?
It only lets light of its colour pass through
What is the pupil and how does it help us see?
A hole in the centre of the iris. It contains muscles that contract and retract to let certain amounts of light through.
What is the lens and how does it help you see?
The lens is a transparent circle of living cells. It can alter its shape to focus a sharp image onto the retina.
What is the retina and how does it help you see?
The retina contains cells that detect light and send messages about it to the brain via the optic nerve.
What is sound?
It is a MECHANICAL method of transferring energy.
Can sound travel in a vacuum and why?
No because sound needs a medium to go through.
How is sound made?
It is made when an object vibrates.
How does sound travel?
When particles vibrate from the vibrating object.
Where does sound travel fastest and why?
Solids because the particles are closest together, so the vibrations travel from particle to particle quicker.
What type of wave is sound?
A longitudinal wave.
What is a longitudinal wave?
A wave when the vibrations are parallel to the direction that the wave is travelling.
What is a wavelength?
The space from one low pressure area (compression) to another or a high pressure area (rarefaction) to another.
What is the frequency?
The number of waves per second.
On a wave diagram, what is the amplitude shown by?
The distance between the top and the bottom per wave.
On a wave diagram, what is the frequency shown by?
The length of each wave.
What is an echo?
A reflection of sound.
What is the pinna and how does it help us hear?
The pinna is the cartilagey bit on the outside of the ear. It helps funnel the sound so it can get into the ear canal.
What is the eardrum and how does it help us hear?
The ear drum is a very thin piece of skin that vibrates wit the sound.
What is the cochlea and now does it help us hear?
It is a snail like tube that is filled with fluid. It sends impulses from sound to the brain.
What is a hearing range?
The lowest to highest frequency that can be heard.
