Visible Light

By Katelyn Fehrenbach, Halie Finke, and Joe Walker

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History/Background

-1666, Newton used prism to separate colors in sunlight

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-People first thought that the prism gave light all it's different colors

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History/Background (con't.)

-proved wrong with Newton's double prism experiment

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-used red

and violet

to discover

infrared &

ultraviolet.

Frequency Range

-each color has different frequency...

---> red: 400-484 THz

orange: 484-508 THz

yellow: 508-526 THz

green: 526-606 THz

blue: 606-668 THz

indigo: 688-714 THz

violet: 714–789 THz

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Wavelength Range

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(See next slide for wavelength comparison)

Speed

-299,792.458 kilometers per second (about 186,282.4 miles per second)

-light could circle Earth more than seven times in one second

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How waves are generated

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-Light waves are the result of the vibrations of electric or magnetic fields

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(see next slide -> atom's electron)

Emitted or Produced by...

• There are many different sources that produce light in our day to day lives.
• Fireflies, Stars, Light Bulbs, the Sun etc.
• Visible light is produced...
• When an atom's electrons become excited with energy and move between different energy levels.
• The excited electrons then emit energy in the form of photons (what light is made of) and then return to their ground state, unless the energy flow is continuous.

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Detected by...

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3:11 to 5:18

Saftey/ Danger (and blocked and shielded by)

• Hazards of Visible light
• Excessive exposure to visible light can possibly lead to macular degeneration (loss of sight in part of the visual field).
• Exposure to certain visible light sources can lead to seizures, due to overstimulation of the brain.
• Too much visible light can cause damage to the retina causing blindness.

Uses/Applications

-help us to see things

-can be made using lasers which are used in compact discs and DVD players

-laser printers, weapon aiming systems

Additional Info

-Visible light waves are the only electromagnetic waves we can see, otherwise known as the colors of the rainbow.

-Each has a different wavelength. Red has the longest and violet has the shortest.

-When two or more of the waves (colors) are seen together, white light is perceived.

Additional Info (con't.)

-Besides a prism, water vapor in the atmosphere also breaks apart the white light, resulting in a rainbow.

-Cones in eyes are the receivers of the waves. The Sun being a natural source, our eyes take in the reflection of sunlight off objects around us.

-The color we see is the color reflected, all other colors are absorbed.

References

http://astronomy.brainbloggers.com/discovery-of-visible-light.html

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http://www.juliantrubin.com/bigten/lightexperiments.html

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http://www.twi.co.uk/technical-knowledge/faqs/health-and-safety-faqs/faq-ultraviolet-visible-and-infrared-radiation-hazards/

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http://scienceprojectideasforkids.com/2010/how-is-visible-light-produced/

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http://www.darvill.clara.net/emag/emagvis.htm

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http://imagine.gsfc.nasa.gov/docs/teachers/lessons/xray_spectra/images/emit.gif

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http://science.hq.nasa.gov/kids/imagers/ems/visible.html

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http://www.physicsclassroom.com/Class/light/u12l2a.cfm

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http://www.windows2universe.org/physical_science/magnetism/em_visible_light.html

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