Sun+protection

Sunshine
 * radiation, heat
 * sun block - windows, screens, chemicals
 * shade - natural - trees. building, materials
 * Vitamin D production
 * sun burn

Sun protection
 * [|sun screen] - SPF, UVA, UVB, broad spectrum - a lotion, spray or other topical product that helps protect the skin from the sun's ultraviolet (UV) radiation, and which reduces sunburn and other skin damage, with the goal lowering your risk of skin cancer.
 * SPF clothing
 * sunglasses - polarized, UV, variable

Why this is important
 * [|Ultraviolet (UV) Radiation and Your Eyes] - Extended exposure to the sun's UV rays has been linked to eye damage, including cataracts, macular degeneration, pingueculae and pterygia and photokeratitis that can cause temporary vision loss.

Most [|sunscreens] work by containing either an organic chemical compound that absorbs ultraviolet light (such as oxybenzone) or an opaque material that reflects light (such as titanium dioxide, zinc oxide), or a combination of both. Typically, absorptive materials are referred to as chemical blocks, whereas opaque materials are mineral or physical blocks.
 * What's the problem?**
 * **Ask** - There are two different types of ultraviolet radiation in sunlight. How can skin damage be prevented from each type of UV radiation?
 * **Imagine** - Ideally, on product would be effective against both kinds of harmful UV radiation. What are the different properties needed? What compounds provide these properties? Are these safe for putting on human skin?
 * **Design, Build** - There are several compounds that provide adequate protection from the sub's radiation. These need to be combined into safe and easy to apply form that can be manufactured and sold at store all over the country. What are some of the factors that go into formulating the product?
 * **Improve** - To simplify application of sunscreen, manufacturers have created new product. Spray-on sun screen is one example of a recent development. What are some other ways that sun screen products have been improved?


 * That's engineering**
 * [|ultraviolet] - part of the electromagnetic spectrum beyond the visible violet light in terms of frequency, wavelength, and energy. Its wavelengths are between about 10 nanometers (nm) about 400 nanometers.
 * UVB (ultraviolet radiation with wavelength between 290 and 320 nanometres), which can cause sunburn
 * UVA (between 320 and 400 nanometres), which damages the skin with more long-term effects, such as premature skin aging.

> radiation, ultraviolet, nanometers, absorption, reflection, electromagnetic, visible, frequency, wavelength, energy
 * Engineering ideas**

Challenges for you to work on...
 * Do It**
 * Find more history and facts about sun screen and sun block.
 * [|UV Radiation beads] - Become a UV detective with beads that detect ultraviolet rays from the sun
 * Show the differences in sunglasses' UV protection with [|sun-sensitive paper]


 * News, updates**


 * Learn more...**
 * UV detecting beads sources - [|1], [[http://www.stevespanglerscience.com/uv-color-changing-beads.html|2

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