Light Flashcards
Light conversion examples
Photosynthesis, solar cells, day-light timing on devices
What is light?
Light is a form of energy
How does light travel?
Light travels in straight lines
Light and energy
Light is a way of transferring energy.
When an object absorbs light, the energy is transferred to heat and the object warms up a little.
How does light travel? (eg. book)
Light from the lamp strikes the book.
Some of the light is reflected into our eye.
To show that light travels in straight lines
Equipment:
3-4 pieces of card
a light source
your eyes
1) Put a hole in the exact same place on you pieces of card.
2) Line them up in a straight line against your light source.
3) Now make an un-even line. What happens?
How fast does light travel?
Light travels at 300,000 km/s
How much faster does light travel than sound? + Give an example
1 million times faster.
Light travels 340 m/s
Eg. thunder and lightning
Transparent
See through it clearly
Opaque
Prevents light through it
Translucent
Allows some light through it
Reflect
Sends the light back - does not absorb it
Absorb
Takes something in
Polychromatic
Produces light in all colours
Shadows
Shadows are formed because light travels in straight lines
Light cannot pass through certain objects
A point source of life will give a dark shadow which is the same shape as the object
Solar eclipse
A solar eclipse is formed when the moon blocks the light of the sun over the earth.
An eclipse will have a central dark area which will be due to no light reaching the earth from the sun.
It will have a outer, lighter area of shadow due to limited light from the sun.
Luminous objects
Luminous objects make and give off their own light.
Eg. The sun, candle (due to chemical reaction), filament in a light bulb (the heated wire becomes white-hor giving off heat and light)
Non-luminous objects
Do not make their own light, they reflect light from another source.
Eg, books reflecting light from the sun outside or the electrical lights.
Examples of non-luminous objects
book chair table mirrors door
Dispersion of light
Dispersion of light is the separating of light into its different colours.
Order of the rainbow
red orange yellow green blue indigo violet
Mirror writing
Mirror writing is laterally inverted so that you can read it properly in the mirror
Convex/converging lenses
A lens that bends the light into a point
Concave/diverging lens
A lens that bends light outwards.
Refraction of light
The bending of light as it passes from one medium to another.
