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The Challenge: Make Sunblock

How can we protect our skin?

Obviously, the best way to protect your skin is by staying out of the sun. Products such as sunscreens and sunblocks will offer good protection from sun exposure. Sunblocks are different from sunscreens. Sunblocks form a physical barrier to the sun: they are opaque creams or pastes that prevent virtually all light from entering the skin by reflecting and scattering UV rays. They include titanium dioxide, zinc oxide, kaolin, talc or iron oxide. A sunscreen contains chemicals that absorb the energy contained in the ultraviolet rays and reflect it away as lower-energy long-wave radiation, which is emitted as heat.

Sun block versus Sun screen