A quick and easy way to show UV light blocked by sunscreen.
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Teachable Topics
- Light & Absorption
- Climate Change
- Skin care
Theory
Sunscreen protects the human body from dangerous exposure to UV radiation by absorbing some fraction of sunlight before it hit the skin.
This experiment uses white paper and/or tonic water as a way to show UV light illuminating a surface. Applying sunscreen to the surface will show that the UV light is absorbed enough to cause a significant dimming of said illumination.
Apparatus
- UltraViolet Light Source
- White Paper
- Tonic Water
- Sunscreen
Procedure
- Position the UV source to light up a piece of paper or glass of tonic water. The surface should appear "kind of blue" under the UV light.
- Apply the sunscreen to the surface and see the effect.
- Note that spray-on sunscreen works best as it is less likely to block visible light as cream-based sunscreen.
Safety
- This experiment presents no safety hazards.
