Uv1

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Uv1

  1. 1. Ultraviolet Lesson 4
  2. 2. What is SPF? Why is it important ?
  3. 3. Sun Protection Factor <ul><li>This is a measure of protection from UVB rays. </li></ul><ul><li>With an SPF 15 sunscreen applied properly, a fair skinned person who burns in 30 minutes can tolerate 15 times 30 minutes (450 minutes) without burning. </li></ul><ul><li>UVA rays are not affected by suntan lotion. </li></ul>
  4. 4. Too much exposure can lead to severe sunburn.
  5. 5. Damage to deep layers is called ‘third degree’ sunburn. outer skin layer middle skin layer deep skin layer First-degree burn Second-degree burn Third-degree burn
  6. 6. Intensity of light and heat The light here is very intense! The light here isn’t so bad... Why? When a body absorbs radiation the amount of energy it gains depends on the intensity (a bit like ‘strength’) and the time of the exposure.
  7. 7. Is a sun-tan really worth it? What are the 3 most important things you’ve learnt today? How will what you have learnt affect your sunbathing behaviour?

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