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General Chemistry Science Fair Project

Octyl Salicylate Concentration and UV Blocking

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Octyl Salicylate Concentration and UV Blocking | Science Fair Projects | STEM Projects
How much sunscreen ingredient does it take to block ultraviolet light? Octyl salicylate is a common UV filter in sunscreen products. You coat five glass sheets with soap mixtures. Each mixture has a different amount of octyl salicylate, from 0 to 8 percent. You place each sheet over a box with a UV meter inside. You compare the UV index reading with and without the coated glass. You discover how the concentration changes the amount of UV radiation that passes through.

Hypothesis

The hypothesis is that higher concentrations of Octyl salicylate in a soap mixture will result in greater blockage of UV radiation.

Science Concepts Learned

UV Absorption

A UV-absorbing material soaks up ultraviolet light instead of letting it pass through. You coat five glass sheets with soap mixtures, each containing a different concentration of octyl salicylate — a common UV filter in sunscreen — ranging from 0 to 8 percent. Each sheet sits over a box with a UV meter inside, placed in direct sunlight. Comparing the UV index reading with and without the coated glass shows that higher concentrations result in greater blockage of UV radiation.

Method & Materials

You will label 5 glass sheets and 5 beakers with 0%, 2%, 4%, 6% and 8%. You will mix alcohol, glycerin and Octyl salicylate in the beakers according to the labels. You will spread the soap solution on the glass surface and allow it to dry. You will place the wooden box in direct sunlight and measure the UV index before and after placing the glass over the box.
You will need 5 glass sheets measuring 500mm x 500mm, 1 UV meter to measure UV index, 1 wooden box with open top, 500 ml alcohol, 250 gram of glycerin, 10 gram of Octyl salicylate, 5 beakers, 1 measuring cylinder, 5 sponges, 1 spatula, and 1 digital weighing scale.

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Results

The experiment showed that increasing the concentration of the Octyl Salicylate in the soap used to coat the glass surface resulted in increasingly lower UV index readings. This means that increased concentrations of Octyl Salicylate resulted in more effective blockage of UV radiation.

Why do this project?

This science project is interesting because it shows how different concentrations of Octyl salicylate in soap mixtures can affect the amount of UV radiation blocked.

Also Consider

Variations of this experiment could include testing different types of sunscreen chemicals like oxybenzone or zinc dioxide, or repeating the experiment indoors using a UV lamp.

Full project details

Additional information and source material for this project are available below.

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