Appendix 8:
Title: The Effect of Sunscreen ingredients on the ability to block UV radiation
Purpose: The purpose of this experiment is to test the ability of sunscreens, containing various active
ingredients, on their ability to block UV radiation.
Materials:
1, 4 quadrant divided petri dish
1 mL Zinc Oxide
1 mL BananaBoat Lotion Sunscreen SPF 60 (chemical based sunscreen)
1 mL Water Babies (?) Lotion Sunscreen SPF 60 (nanomaterial containing sunscreen)
60 UV Beads
4, 3cc syringes
Goggles
Vinyl or Latex Gloves
Sharpie pen
Stopwatch, or watch with second hand
Procedure:
1. Using the sharpie marker, draw 2 lines on the top of the petri dish marking the 4 quadrants. Write a
very small 1, 2, 3 or 4 in each quadrant.
2. Using the sharpie, label the bottom of the petri dish so that one quadrant is marked 1, 2, 3, or 4.
3. Place 15 UV beads into each quadrant, and place the lid back onto the dish. Make sure to line up the
quadrants with the corresponding numbers on the top and bottom.
4. Put your gloves on and keep them on until you are done handling the sunscreens.
5. Suction 1 mL of zinc oxide into a 3cc syringe.
6. Slowly push the plunger down and release this sunscreen onto the top of the petri dish marked with
the #2. Gently, spread the zinc oxide around covering the entire top of quadrant 2 and the side of the
dish associated with quadrant 2. This sunscreen will still be thick and white.
7. Repeat steps 5 and 6, placing BananaBoat sunscreen onto the top and sides of Quadrant 3, and
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sunscreen on the tops and side of Quadrant 4. Try to get these sunscreens
to be fairly clear.
8. Carefully, pick up the petri dish, and rest the bottom, in the palm of your hand.
9. Carry the dish towards the outside sunshine.
10. Begin the stopwatch, and place in the sunshine at the same time.
11. Hold the dish in the sunshine for 2 minutes.
12. Take the dish to a shady area.
13. Record your results in the data table, using +++++ for maximum UV absorbance, ++++, +++ ++, +,
and – for no detectable absorbance of UV light.
14. The +++++ will be based on the color of the beads in Quadrant 1, your control.
Results:
Table 1: Color of the UV Beads following exposure to UV light
Quadrant
1
Contents
Clear
2
Zinc Oxide
Color of Beads
3
SPF 60; octocrylene + oxybenzone +
avobenzone
4
SPF 60; zinc oxide + titanium dioxide
Conclusions:
1. What was the purpose of including Quadrant 1 in this experiment?
2. Referring back to your experimental design diagram, write down your hypothesis.
3. What sunscreen(s) was the best at blocking UV light? How did you know this?
4. Does the data that you collected support your hypothesis? Why or why not?
5. What were 2 possible sources of error? Describe what part of your experiment that they may have
impacted, and what could be done to avoid this is in a future experiment.
6. Based on your findings, what future experiment would you like to perform?