The sun emits harmful UV rays year-round. Even on cloudy days, up to 80 percent of the sun’s harmful UV rays can penetrate your skin. Sunlight consists of two types of harmful rays that reach the earth — UVA rays and UVB rays. Overexposure to either can lead to skin damage. In addition, here are other effects of what each of these rays can do:
For criteria and constraints, it’s up to you to figure them out! It’s suggested that you put the same number of beads in the same kind of bag. The testing protocols are yours to choose, but just make sure everything you conduct is a fair test.
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