1. U.V. Rays Eliza Burr, Sydney Appelbaum, and Brittany Tedford-Riley

2. 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.

3. What Are U.V. Rays? U.V. Rays lie between Visible Light waves and X-Rays on the Electromagnetic Spectrum.

4. What are U.V. Rays? The wavelength is between 4x10 -7 meters and 1x10 -8 meters. The frequency is between 10 15 Hertz and 10 17 Hertz.

5. 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.

6. How Were U.V. Rays Discovered?

7. 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

8. Types of U.V. Rays

9. 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

10. 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

11. Uses for U.V. Rays Dental Practices

12. 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

13. PROTECT YOURSELF: USE SUNSCREEN