U.V. Rays

Eliza Burr, Sydney Appelbaum, and Brittany Tedford-Riley

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What Are U.V. Rays?

• U.V. (or Ultra Violet) Rays are what comes from the sun, what causes our sunburns, what helps bees pollinate.

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What Are U.V. Rays?

• U.V. Rays lie between Visible Light waves and X-Rays on the Electromagnetic Spectrum.

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What are U.V. Rays?

• The wavelength is between 4x10-7 meters and 1x10-8 meters.

• The frequency is between 1015 Hertz and 1017 Hertz.

How Were U.V. Rays Discovered?

• Discovered in 1801 by Johann Wilhem Ritter.

• Ritter was born on December 16, 1776 in Samitz, Germany.

• While doing an experiment with silver chloride, Ritter found that it was darkened by a substance beyond visible light…Ultra Violet Light.

How Were U.V. Rays Discovered?

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Types of U.V. Rays• UVA:

– very similar to visible light– is the most harmful to the eyes

• UVB:– wavelength is 2.8x10-7 meters to 3.15x10-7 meters– Causes tans and most skin damage, including

cancer

• UVC:– wavelength is 1x10-7 meters to 2.8x10-7 meters– Earth’s atmosphere blocks most of these, but they

slowly deplete the ozone– Most harmful type

Types of U.V. Rays

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Who Can See U.V. Rays?

• Humans can’t see them

• Some insects can see them and often mistake them for the sun’s rays.– Bumblebees use U.V. Rays to find pollen in

flowers

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Uses for U.V. Rays

• Forensics: identifying bodily fluids• Florescent lamps• Helps make Vitamin D for bones• Treats skin diseases such as psoriasis, lupis

vulgaris, and tuberculosis• Kills bacteria• Dental practices: helps glue dryMinerology:

identifies minerals• Detects forgeries in artwork• Astronomy: can identify planets and stars• Ultra Violet fly traps

Uses for U.V. Rays

• Dental Practices

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Are U.V. Rays Harmful?

• U.V. Rays make up 7% of the sun, but only half that reaches the earth – If all the U.V. Rays in the sun reached earth, they

could kill living things

• Sunburns are caused 15 minutes after exposure to UVB rays

• Can cause wrinkles, melanomas, and damage cataracts

PROTECT YOURSELF: USE SUNSCREEN

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