Light
Light is a type of energy and comes from the sun. It travels from the Sun through Space at the highest speed.
During the day, we see by sunlight and at night, we use electric lights to see.
History of lamp
Early people burned animal oil in stone lamps to make light.
And then wax candles were used.
About year 1800, we used oil lamps.
Today and future, we use electric lamps.
Light effects
Transparent
Translucent
Opqaue
Glass mug is transparent. It lets light pass through.
Plastic bag is translucent. It lets some light through.
Cardboard is opaque. You can see through it at all.
Colours of light
Red, green and blue are the primary colours of light. This is used for TVs, computer screen, etc.
Secondary colours:
Green+Blue=Cyan, Red invert into Cyan
Red+Blue=Magenta, Green invert into Magenta
Red+Green=Yellow, Blue invert into Yellow
Red+Green+Blue=White, Whhite invert into Black