...Light...
Light is a form of energy and it travels in lines which are straight.
Refraction of light is when those straight lines of light change direction and bend a bit
because of it passing through objects of different densities at different speeds. such as
light travling from air into glass. Another word for these objects is Medium. Light
travels at slightly different speeds in different mediums, hence the bending. Each object has an optical
density. This is a measure of how slow the light travels in that material. The higher the optical density, the slower
the light travels in that material. (vaccuum has the optical density of 1.0, so it travels at 300,000kmps,
and dimond has an optical density of 2.4, so it travels at 125,000kmps. Imagine it like a bullet,
it wil pass through the air faster than it will pass through a brick wall, but in this case, its not a bullet its a light
ray.) The light ray moving towards the boarder between mediums is called the incident ray. The
light ray that has entered the seccond medium is called the refracted ray. An imaginary line at
right angles to surface of the medium is called the normal. The angle
between the incident ray and the normal is called the Angle of incidence. The angle between the
refracted ray and the normal is called the angle of refraction.
...Light entering a more dense medium...
As light travels into a dense medium, such as from air into glass. The angle of incidence is greater than the angle of
refraction. The light ray bends towards the normal.
...Light entering a less dense medium...
As light travels into a less dense medium, such as from glass into air. The angle of incidence is less than the angle
of refraction. The light bends away from the normal
Light travels at 3,000,000 kmps, thats about 7.5 times around the world each seccond.
Nothing is faster. But it takes about 8 minutes to reach the earth from the sun. A light Sorce
gives out its own light, such as the sun. reflectors of light dont make thier own light, they just reflect it to make
it look like they do, like then moon.
...Reflection of light...
A light ray (traveling in straight lines) hits an object (for example a mirror) and reflects
off it. The light ray bounces back off the object at the same angle that it came in away from the
normal.
...Absorption of light...
Absorption = Take in or soak up
Light Absorption = When light shines on an object it can absorb it.
This means the object soaks up the light (e.g. wearing a black jersey out in the sun, the jersey will absorb the light
and convert a light energy to heat therefore, the person will heat up quickly.)
...Colours of light...
Red, orange, yellow, green,
blue, indigo, violet. Then you go into dangerous
rays called ultra violet.
...Light meters...
A way of measuring the amount of light that is present.
They give a reading on a screen. They look like little calculators, with a microphone, but not. The unit of light intensity
in Lux.
