Download presentation
Presentation is loading. Please wait.
1
The Production of Light
Shedding some light on the world…
2
How We See We see by light entering our eyes
This happens in 1 of 2 ways: Luminous objects create their own light Light bulb, Sun, TV Non-Luminous objects only reflect light Paper, planets, desks
3
How Light is Produced Luminous Objects produce their own light in a variety of ways. For example: Incandescence Electric Discharge Phosphorescence Fluorescence Chemiluminescence Bioluminescence Triboluminescence Light-Emmiting Diode (LED) LASER
4
Incandescence Producing light from a glowing hot object
Colours produced depend on the temperature As temperatures increase, colours change from red, to yellow, to white, to a blueish-white. Examples: Stove, fire, incandescent light bulb
5
Electric Discharge Producing light by passing electric current through a gas Electrons are excited to higher orbits and then emit light when they fall back down Different gasses produce different colours Examples: Lightening, neon lights
6
Phosphorescence Producing light by absorbing UV light and emitting visible light over time Phosphors store the energy until later Examples: Glow in the dark stickers, some watches
7
Fluorescence Producing light by absorbing UV light and emitting visible light immediately Examples: Fluorescent lights, “black lights”, highlighters
8
Fluorescent Lights Makes use of electric discharge and fluorescence
Electric discharge in the tube causes mercury in the tube to emit UV light Fluorescent materials on the outer wall of the tube then glow in the visible range They don’t emit true white light, just a few distinct colours
9
Chemiluminescence Production of light as the result of a chemical reaction Little to no heat is produced No electric current required Examples: Glow sticks
10
Bioluminescence Chemiluminescence occurring in a living organism
Developed for various reasons Examples: Firefly, Glow worm, Anglerfish
11
Triboluminescence Production of light from friction
Certain crystals produce light when crushed, rubbed or scratched No known practical applications Examples: Eating wintergreens hard candy
12
Light-Emitting Diode (LED)
Producing light by passing electricity through a semi-conductor Semi-conductor: A material allowing electricity to pass in one direction only Low heat produced and very energy efficient Examples: Glowing light on electronics, Christmas lights, traffic lights
13
LASER Light Amplification by Stimulated Emission of Radiation
Produced using either special gasses or crystals Laser light is all one colour (wavelength) traveling in a very narrow, focused beam High and low energy lasers are available
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.