Ultraviolet Lesson 4
What is SPF? Why is it important ?
Sun Protection Factor <ul><li>This is a measure of protection from UVB rays. </li></ul><ul><li>With an SPF 15 sunscreen ap...
Too much exposure can lead to severe sunburn.
Damage to deep layers is called ‘third degree’ sunburn. outer skin layer middle skin layer deep skin layer First-degree bu...
Intensity of light and heat The light here is very intense! The light here isn’t so bad...  Why? When a body absorbs radia...
Is a sun-tan really worth it? What are the 3 most important things you’ve learnt today? How will what you have learnt affe...
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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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