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Light and Colour

Light and Colour. What’s it for?. Without light there would no life on Earth Allows plants to grow Provides warmth Delivers info (TV, computer, phone) Used in learning and entertainment. What is it?. Light is a form of energy that you can detect with your eyes

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Light and Colour

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  1. LightandColour

  2. What’s it for? • Without light there would no life on Earth • Allows plants to grow • Provides warmth • Delivers info (TV, computer, phone) • Used in learning and entertainment

  3. What is it? • Light is a form of energy that you can detect with your eyes • Light energy comes from other forms of energy like chemical energy, electrical energy, and nuclear energy

  4. Where does light energy come from? • Light energy can come from many different sources, both natural and artificial • The sun is the most important natural light source • Artificial sources of light are produced by humans

  5. Luminous and Nonluminous • Luminous objects give off their own light like the sun or a flashlight • Objects that do not give off their own light are nonluminous • In luminous objects some form of energy turns into light energy

  6. Incandescence • Thins that are extremely hot become luminous. At high temperatures they begin to emit light • The process of emitting light due to high temperatures is called incandescence • Electrical energy changes into heat and light energy in an incandescence lightbulb

  7. Electrical Discharge • When electricity passes through a gas, the gas particles can emit light. This process is called electrical discharge • Lightning and neon lights are examples

  8. Phosphorescence • Certain materials called phosphors can give off light after light has been shined on them for a short time • The process of emitting light after receiving energy from another source is called phosphorescence

  9. Fluorescence • Fluorescence is the process of emitting light while receiving energy from another source • In fluorescent lights, electricity hits molecules of mercury vapour, causing them to emit ultraviolet (UV) energy. Then the ultraviolet energy hits a phosphor coating on the inside of the tube. This emits the light that you see!

  10. Chemiluminescence • The process of turning chemical energy into light with very little change in temperature is called chemiluminescence • Glow sticks are examples

  11. Bioluminescence • Some living creatures can make themselves luminous by using chemical reactions • Fireflies are an example

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