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Sunscreen soap and UV radiationFeatured science projectScience project video


This science fair project was conducted to ascertain the effectiveness of sunscreen soap in providing protection against ultraviolet radiation from the sun. The tests were done using different concentrations of Octyl-salicylate mixed in glycerin (soap ingredient) and alcohol.


Higher concentrations of Octyl salicylate in soap mixtures are able to block a greater amount of UV radiation.

Scientific Terms

Ultraviolet radiation, Sun Protection Factor (SPF), organic, inorganic, Octyl salicylate



Sunscreen lotions or soaps are used to block, absorb or reflect ultraviolet radiation from the sun. They are applied to our skin for protection from the sun’s ultraviolet rays and help in the prevention of sunburn.

The effectiveness of a sunscreen is measured by their Sun Protection Factor (SPF) rating. A higher SPF rating generally means greater protection from the sun’s UV-B radiation (the ultraviolet ray that causes skin sunburn). The amount of protection from UV-B radiation will depend on our skin type, the amount of sunscreen applied, the amount of sweat or type of activity involved and the amount of sunscreen absorbed by the skin.

Sunscreens are made using substances that filter ultraviolet rays. These materials are organic compounds, organic particulates or inorganic particulates. Octyl salicylate is an organic compound that is used to absorb UV-B radiation from the sun. It is a colorless and oily liquid.

UV index

The simplest way of measuring ultraviolet radiation is the UV index. Each unit on the UV index represents about 25mW per square meter of UV radiation. The UV index range is described as follows:

Less than 3: Moderate levels

Between 3 and 6: High levels - enough to cause sunburn even at temperatures below 27 degrees Celsius

Between 7 and 9: Very high levels - enough to cause sunburn on cloudy days

More than 9: Extreme levels - that can cause sunburn to an unprotected skin within 12 minutes.

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Complexity level:
Project cost ($):
Time required:
1 hour to prepare, 1 hour for the science project experiment
Material availability:
May be found at a hardware store, and a chemist
Safety concerns:

Avoid long, unprotected exposure to the sun. Handle glass extremely carefully. Adult assistance required.