The Challenge: Make Sunblock
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With temperatures reaching 95°F and an unforgiving sun overhead, would botanist
Ellen be able to find a natural sunblock to save the scientists' complexions?
Why does our skin get harmed by the sun?
Three kinds of ultraviolet (UV) light come from the sun:
A (UVA) rays are the longest of the three with wavelengths
(400-315 nanometers) that penetrate deep into the layers of skin
causing tissue damage and wrinkling.
B (UVB) rays have shorter wavelengths (315-280 nanometers)
and are known to mainly cause sunburn and skin cancer.
rays are very short (280-100 nanometers) and the ozone layer is
designed to protect us from these deadly rays.
How does our skin become tanned?