Ultraviolet

→ Comes from the Sun and man-made sources like tanning beds and welding torches.
→ Most skin cancers are a result of exposure to UV rays in sunlight.

• Beyond violet (Latin origin).
• The Sun is the main source of ultraviolet, though the more dangerous wavelengths are absorbed by the atmosphere, particularly the ozone layer.

► Beyond violet – beyond what our eyes can see on the violet side of the rainbow.

• Ultraviolet radiation has both positive and negative effects on the human body.
  → UV radiation in sunlight can cause suntan and help produce vitamin D in our skin.

• UV radiation (shorter wavelength) can be used as a sterilizing agent to kill germs and bacteria on hospital and laboratory equipment.

• Also used to identify counterfeit bills – the numbers on each banknote are printed with fluorescent chemicals that become visible under a UV lamp.

• Discovered by Johann Wilhelm Ritter.

• Responsible for tanning and sunburn, two things that can lead to skin cancer.

 3 Kinds of UV

  1. UVA – 95% of the solar UV reaching the Earth.

  2. UVB – filtered by the ozone in the atmosphere.

  3. UVC – almost completely absorbed by the atmosphere and no longer reach the surface of the earth.