Light and Optics

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Light and Optics

• Have you ever wondered?
• why the sky is blue
• how some animals can see in the dark
• if fireflies really glow
• how your eyes work

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What is Light?

• it is made up of both a particle a wave
• the particle is called a photon
• light is a form of energy you can see
• the faster the waves move the more energy there
  is and the more light
• light spreads out or radiates from its source
• it can then be absorbed by a surface
• or transformed into other energy
• thermal, electrical or chemical

Did you Know? Less than one billionth of a
percent of the Suns energy actually reaches the
Earth
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Where does light come from?

• natural light sources
• the sun and stars
• it takes the suns radiant energy 8 minutes to
  reach Earth
• fire
• reflection from the moon
• bioluminescence
• artificial light sources
• light bulbs
• glow sticks

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Sources of Light

• nuclear fusion ? the sun
• it takes the suns radiant energy 8 minutes to
  reach Earth
• light from electricity
• incandescent light bulbs electrons move, create
  heat produce light regular light bulb
• fluorescent bulbs electricity excites gases,
  they move faster emit light energy
  efficient light bulb
• light from phosphorescence
• energy absorbed by phosphorescent material,
  stored, then released slowly as light glow in
  the dark
• light from chemical reactions
• fire (fuel and oxygen give off light and heat)
• bioluminescence (some organisms have chemical
  reactions that produces light
• we make things with chemicals that can produce
  light (e.g. glow sticks)