Testing Sunscreen Effectiveness
Hard
We're going to measure the absorbance of sunscreen to determine its effectiveness at blocking UV light. We'll make a series of solutions with different concentrations and measure the absorbance of each. Then we'll compare the extinction coefficients of different SPF factors to determine their relative effectiveness.
Hypothesis
The hypothesis is that the higher the SPF rating, the more effective the sunscreen will be at blocking UV light.
Method & Materials
You will work in groups of four to dissolve the sunscreens in ethanol, make a series of ethanol solutions with different concentrations, measure the absorbance of the different dilutions, and plot the absorbance of the sunscreen vs. concentration to calculate the extinction coefficient.
You will need a 50.00 mL volumetric flask, a 50 mL beaker, a 250 mL beaker, a 1.00 mL graduated pipet, a digital balance, a HP 8453 UV-Visible Spectrophotometer, 95% ethanol, and a sunscreen product.
Results
The results of this experiment show that the higher the SPF rating, the more effective the sunscreen is at blocking UV light. This is an important finding, as it helps us understand how to better protect our skin from the sun's harmful rays.
Why do this project?
This science project is interesting and unique because it allows us to measure the effectiveness of sunscreen in a quantitative way.
Also Consider
Experiment variations to consider include testing different types of sunscreen, such as mineral-based or chemical-based, or testing different SPF ratings.
Full project details
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