waves and technology
carriers of energy
identify, with the use of examples the transfer of energy by waves
mechanical (sound waves, earthquake and surface water waves)
electromagnetic (radio, x-rays, gamma rays and visible light)
compare longitudinal (compression) waves and transverse waves
longitudinal waves’ medium moves in the same direction as the wave, and the movement of the particles of from left to right and forces other particles to vibrate.
in a transverse wave the medium moves perpendicular to the direction of the wave, the particles also move up and down as the wave moves horizontally.
recognise the difference between mechanical and electromagnetic waves
mechanical waves require a medium (a substance or material that carries a wave) to propagate
electromagnetic waves do not require a medium to spread
describe frequency
the number of complete wave cycles that pass a given point in a certain amount of time, measured in hertz
describe period (T)
the amount of time it takes to complete one cycle
describe wavelength
the distance from crest to crest or from one trough to trough
state the equation for speed
speed= wavelength x frequency
v= λ x f
examine how sound waves pass through the ear to allow us to hear
sound waves enter the outer ear and travel through the ear canal, leading to the eardrum. The eardrum then vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear.
is visible light a form of electromagnetic radiation?
yes, all electromagnetic radiation is light
recall the different electromagnetic waves
radio
microwave
infrared
x- ray
ultraviolet
gamma ray
visible light
identify the properties and uses of electromagnetic waves
properties: wavelength, frequency and speed
they can propagate through vacuum and mediums
they can be absorbed, reflected, refracted or transmitted by matter
describe the reflection of light from plane and curved mirrors and identify some useful applications
mirrors can be flat or curved.
flat mirrors= used in bathrooms and cars
curved mirrors= used in security cameras, they an make things look bigger or smaller
explain how images are formed when light passes from one medium to another of different optical density
When light passes from one medium to another with a different optical density, it bends. This is called refraction. The bending of light causes the image to appear in a different position than its actual location. The amount of bending depends on the angle of incidence and the refractive indices of the two media.
outline everyday instances in which refraction is evident
a spoon appearing bent when placed in a glass of water
a rainbow formed by sunlight refracting through water droplets
distinguish between reflection and refraction
reflection= light bounces back from a surface
refraction= light bends as it passes from one medium to another
describe the different types of lenses and how they work to focus light
convex lenses= thicker in the middle than at the edges. they converge parallel light rays to a focal point
concave= thinner in the middle than the edges. they diverge parallel light rays
identify applications of lenses
cameras
telescopes
microscopes
eyeglasses
colour and vision
recall how the eye functions to provide vision
the eye works by focusing light on the retina, where photoreceptor cells (rods and cones) convert light into electrical signals that are sent to the brain
account for the colour of objects in terms of absorption, transmission and reflection of the colour spectrum
the colour of objects depends on the wavelengths of light it absorbs and reflects
(e.g. a red object reflects red light and absorbs other colours)
outline the function of the retina in relation to vision
the retina contains photoreceptor cells that detect light and transmit information to the brain
describe some familiar examples of scattering and dispersion
scattering- the random scattering of light in all directions
dispersion- the separation of white light into it component colours (e.g.) a rainbow
carriers of energy
identify, with the use of examples the transfer of energy by waves
mechanical (sound waves, earthquake and surface water waves)
electromagnetic (radio, x-rays, gamma rays and visible light)
compare longitudinal (compression) waves and transverse waves
longitudinal waves’ medium moves in the same direction as the wave, and the movement of the particles of from left to right and forces other particles to vibrate.
in a transverse wave the medium moves perpendicular to the direction of the wave, the particles also move up and down as the wave moves horizontally.
recognise the difference between mechanical and electromagnetic waves
mechanical waves require a medium (a substance or material that carries a wave) to propagate
electromagnetic waves do not require a medium to spread
describe frequency
the number of complete wave cycles that pass a given point in a certain amount of time, measured in hertz
describe period (T)
the amount of time it takes to complete one cycle
describe wavelength
the distance from crest to crest or from one trough to trough
state the equation for speed
speed= wavelength x frequency
v= λ x f
examine how sound waves pass through the ear to allow us to hear
sound waves enter the outer ear and travel through the ear canal, leading to the eardrum. The eardrum then vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear.
is visible light a form of electromagnetic radiation?
yes, all electromagnetic radiation is light
recall the different electromagnetic waves
radio
microwave
infrared
x- ray
ultraviolet
gamma ray
visible light
identify the properties and uses of electromagnetic waves
properties: wavelength, frequency and speed
they can propagate through vacuum and mediums
they can be absorbed, reflected, refracted or transmitted by matter
describe the reflection of light from plane and curved mirrors and identify some useful applications
mirrors can be flat or curved.
flat mirrors= used in bathrooms and cars
curved mirrors= used in security cameras, they an make things look bigger or smaller
explain how images are formed when light passes from one medium to another of different optical density
When light passes from one medium to another with a different optical density, it bends. This is called refraction. The bending of light causes the image to appear in a different position than its actual location. The amount of bending depends on the angle of incidence and the refractive indices of the two media.
outline everyday instances in which refraction is evident
a spoon appearing bent when placed in a glass of water
a rainbow formed by sunlight refracting through water droplets
distinguish between reflection and refraction
reflection= light bounces back from a surface
refraction= light bends as it passes from one medium to another
describe the different types of lenses and how they work to focus light
convex lenses= thicker in the middle than at the edges. they converge parallel light rays to a focal point
concave= thinner in the middle than the edges. they diverge parallel light rays
identify applications of lenses
cameras
telescopes
microscopes
eyeglasses
colour and vision
recall how the eye functions to provide vision
the eye works by focusing light on the retina, where photoreceptor cells (rods and cones) convert light into electrical signals that are sent to the brain
account for the colour of objects in terms of absorption, transmission and reflection of the colour spectrum
the colour of objects depends on the wavelengths of light it absorbs and reflects
(e.g. a red object reflects red light and absorbs other colours)
outline the function of the retina in relation to vision
the retina contains photoreceptor cells that detect light and transmit information to the brain
describe some familiar examples of scattering and dispersion
scattering- the random scattering of light in all directions
dispersion- the separation of white light into it component colours (e.g.) a rainbow