Type of UV blocker (SPF 15, SPF 50, physical cloth, coin)
Dependent Variable
Intensity of the blue color (UV Blocking Rank 1-5)
Constants
Exposure time, angle of the sun, brand of paper, rinse time
Reflection Questions Guidance
1. Hypothesis Support
Students should reference their data directly. Example: "My hypothesis was supported because the SPF 50 had a rank of 4, while the SPF 15 only had a rank of 2."
2. Effective Blockers
Opaque physical objects usually win. Students should identify "opacity" or "thickness" as the property. For sunscreen, they should note it "absorbs" or "reflects" the energy.
3. SPF Difference
Depending on sun intensity, students may see a slight difference. If they don't, discuss "saturation" — once the paper is cooked, more protection doesn't make it "whiter."
4. Real-World Connection (Hazy Days)
Critical Concept: UV radiation is high-energy and can penetrate clouds. Even if it doesn't feel "hot" (visible/infrared), the UV "attacker" is still present and chemically active.
Safety Note
Sun paper chemicals are generally safe, but students should wash hands after handling paper and sunscreen. Avoid contact with eyes. Ensure students wear sunglasses if working in direct, bright sunlight for extended periods.
