Sunday, July 1, 2007

How Does Sunscreen Work?

The sun is a gigantic atom-smashing machine that makes heat and light. It is the reason why you can enjoy a day at the beach or a dip in the pool, especially on a hot summer day.


The sun also emits harmful UV rays that are responsible for sunburns; too much exposure can cause skin cancer.

What’s Inside?
Sunscreen contains chemicals that reflect or absorb harmful UV rays. When applied to the skin, the thin layer of sunscreen does not allow UV rays to touch your skin.
Sunscreen has to be reapplied every few hours because swimming and sweating washes it off. Did you know that UV rays also damage the chemicals in sunscreen? It’s true! Sunscreen works because the chemicals are being sacrificed to save the skin!

Why do some lifeguards look like they are wearing white paint on their nose?

That white stuff is zinc oxide; another common chemical is titanium dioxide. Both of these chemicals reflect UV rays.

Other kinds of chemicals absorb UV rays. These have funny names like oxybenzone and avobenzone. There’s a long list of chemicals found in different sunscreens.

Did you know that these chemicals are also found in lip balm, lotions, and make-up?

If you feel adventurous, read the ingredient label on the back of a box. I know that there are many funny chemical names, but look for the ones you know!

SPF
How do you know the strength of the sunscreen? The standard is called Sun Protection Factor, or SPF.

Sunscreen with a higher SPF rating means that it has more chemicals in it that absorb or reflect UV rays.

Dr. Dave’s Tips
  • Wear sunscreen if you are going to be outside for a long time.
  • Reapply sunscreen after swimming.
  • Wear a hat and sunglasses to protect your eyes!
That’s all for now!

Dr. Dave

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