TITLE: Experiment- Testing Sunscreens

NAME: Shelly Crow

EMAIL: crows@tisd.net

KEYWORD: lab, SPF factors of sunscreen, protection from sun

TEXT:

Materials: (per person or per group)

1. 1 transparency or acrylic sheet
2. 6 types of sunscreens with different SPF factors (number of different types varies)
3. one piece of photosensitive or blueprint paper
4. permanent marker or transparency pen
5. strip of cloth (about 6 inches long)

Experiment: (have students predict which sunscreen they think will work best and explain why)

1. draw 6 rectangles on the transparency with marker
2. label each rectangle with the corresponding SPF number of the sunscreen
3. spread on each rectangle a small, even, amount of each corresponding sunscreen with a cotton swab (use different cotton swab with each sunscreen)
4. staple or tape the strip of cloth to transparency
5. lay transparency over the sun-sensitive paper, take outside and lay paper on a flat surface (be sure to write the number of your sample on the sun-sensitive paper as well)
6. leave paper in sun until the sun-sensitive paper turns a very light color (three seconds to three minutes, depending on the paper and brightness of area)
7. take setup back into the classroom and remove transparency
8. record shading under each SPF and cloth (dark blue to white)

Questions:

1. Which sunscreen(s) worked the best? Explain why.
2. Graph the results of your experiment.
3. Of the samples tested, what is the best protection against a sunburn?
4. Which sunscreen would you buy? Why?
5. Why are most sunscreens white?

Extension Activities:

1. What is the SPF factors?
2. Do a survey on public preferences on sunscreens. (Have students graph results)
3. Compare ingredients of different sunscreens and create a comparison chart.
4. Create a poster presentation on the hazards of the sun on living organisms.
5. Have students check a control setup over a longer period of time (every five minutes).

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