Taylor - Ultraviolet Light


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Taylor - Ultraviolet Light

  1. 1. Before we get started
  2. 2. Ultraviolet Light By: Taylor Stommel
  3. 3. Discovery <ul><li>discovered by Johann Wilhelm Ritter, a German physicist </li></ul><ul><li>also credited with the invention of dry cell and dry storage batteries, in 1801 </li></ul>
  4. 4. What is it? <ul><li>a type of electromagnetic radiation </li></ul><ul><li>has a wavelength shorter than that of visible light but longer than that of and x-ray; approximately 300 to 400 nanometers of radiation </li></ul><ul><li>degrades the components of paper, photographs, inks, paints, and adhesives </li></ul>
  5. 5. How does it work? <ul><li>every radiation substance produces ionization energy </li></ul><ul><li>ionization energy below the ultraviolet spectrum is largely absorbed by matter </li></ul><ul><li>as you go higher up the spectrum, the ionization levels of many of the molecules in matter exposed to UV light is reached </li></ul><ul><li>. when the ionization level is reached, photoionization takes place </li></ul>
  6. 6. How does it work? continued… <ul><li>photoionization is dangerous because UV photons above the ionization energy can damage and/or alter atoms and molecules </li></ul><ul><li>a high level UV or X-ray will mot be absorbed </li></ul><ul><li>Ultraviolet is repelled by the melonin content in your skin (we’ll get to that later </li></ul>
  7. 7. The Spectrum <ul><li>the spectrum of light recognized as ultra violet light is further divided into three subgroups, UVA, UVB, and UVC, with UVA rays having the shortest wave length and UVC having the longest </li></ul><ul><li>Keep in mind that the longer the wavelengths of a light on the ultraviolet section of the electromagnetic spectrum, the closer it is to what we know as visible light </li></ul>
  8. 8. Natural Sources <ul><li>the sun </li></ul><ul><li>most UVB and UVC rays are absorbed into the ozone layer </li></ul><ul><li>98.7% of all the ultraviolet radiation that ever reaches the surface of the earth is UVA </li></ul>
  9. 9. Health Related Effect on Humans
  10. 10. Benefits <ul><li>UVB exposure increased the production of vitamin D in the skin </li></ul><ul><li>vitamin D deficiency leads to some kinds of cancer and thousands of premature deaths annually </li></ul>
  11. 11. Consequences <ul><li>too much UVB radiation results in direct damages to the DNA and sunburn </li></ul><ul><li>melonin production goes up as the DNA is repaired </li></ul><ul><li>melonin is a component that causes your skin tone </li></ul><ul><li>melonin disopates ultraviolet light and energy as harmless heat and prevents direct and indirect UV damage </li></ul>
  12. 12. So…What about that suntan? <ul><li>limited sun exposure (tolerance varies by skin tone) will reduce the damage </li></ul><ul><li>sunscreen only protects against direct DNA damage, so you might want to wear a hat </li></ul>
  13. 13. Applications of Ultraviolet Light
  14. 14. Security <ul><li>in order to avoid having a counterfake mistaken as a real item, many creditcards, drivers lisenses, passports, etc. contain a UV water mark </li></ul><ul><li>ex visa card </li></ul>
  15. 15. Forensics <ul><li>helpful in locating and recognizing bodily fluids </li></ul><ul><li>ex: blood </li></ul>
  16. 16. Astronomy <ul><li>very hot objects emit UV radiation (ex: stars and some planets) </li></ul><ul><li>can be used to identify kind of star </li></ul><ul><li>because the ozone layer blocks most UV rays, most observations are made from space </li></ul>
  17. 17. Authentication <ul><li>can identify paintings and collectables, even dollar bills </li></ul><ul><li>different objects and substances flouresce differently under ultraviolet light </li></ul>
  18. 18. In public places…? <ul><li>installed in public restrooms and on public transit </li></ul><ul><li>to deter the use of substance abuse </li></ul><ul><li>the blue coloring of the lights and the natural florescence of the skin make it harder for intravenous drug users to find a varicose vein </li></ul>
  19. 19. Evolutionary Significance <ul><li>because UV light causes damage to the DNA, especially thymine bases, as it causes them to bond together into thyminedimers </li></ul><ul><li>these dimmers cannot be replicated during reproduction and result in variations in offspring in even asexual organisms </li></ul>
  20. 20. Bibliography <ul><li>en.wikipedia.org/wiki/Ultraviolet Ultraviolet.&quot; wikipedia . 020209. wikipedia. 5 Feb 2009 <en.wikipedia.org/wiki/Ultraviolet>. </li></ul><ul><li>Doran, Ysabel. &quot;Who Discovered Ultraviolet Light?.&quot; ehow . 5 Feb 2009 <http://www.ehow.com/about_4588280_who-discovered-ultraviolet-light.html>. </li></ul><ul><li>Dubbs, Lindsay. &quot;Ecological impacts of UV-B radiation.&quot; biology.duke.edu . 000405. duke education. 5 Feb 2009 <http://www.biology.duke.edu/bio217/2005/lld20/index.html>. </li></ul><ul><li>&quot;UVA UVB skin.&quot; fda.gov . food and drug administration. 5 Feb 2009 <http://www.fda.gov/cdrh/tanning/uv_types.jpg>. </li></ul><ul><li>Nave, R. &quot;Interaction of Radiation with matter.&quot; hyperphysics.phy . hyperphysics. 5 Feb 2009 </li></ul><ul><li>Nave, R. &quot;interaction of radiation and matter.&quot; hyperphysics education . 5 Feb 2009 <http://hyperphysics.phy-astr.gsu.edu/hbase/mod3.html#c5>. </li></ul>
  21. 21. The End