Question

Julie is testing to see if increasing the Sunburn Protection Factor (SPF) of her sunscreen protects against sunburn better than the SPF 15 she always uses. Julie gets 4 identical panels of clear glass, UV sensitive paper (to indicate harmful sunlight), and 4 sunscreens of the same brand with different SPF. Julie smears equal amounts of SPF 15, SPF 30, SPF 45, and SPF 50 sunscreen evenly on the panels of glass. The glass panels are placed over UV sensitive paper in the sun at the same location for 4 hours.

What would be the best control group for Julie’s experiment? (SC.912.N.1.1)
A.a glass panel with the SPF 15 sunscreen
B.a glass panel with the SPF 30 sunscreen
C.a glass panel with the SPF 45 sunscreen
D.a glass panel with the SPF 50 sunscreen

Answer 1

Answer: A. a glass panel with the SPF 15 sunscreen.

Step-by-step explanation:

The best control group for Julie's experiment would be a glass panel with no sunscreen applied to it. The control group is used as a baseline for comparison, and in this case, the control group would allow Julie to determine the effect of the sun's UV rays on the UV sensitive paper without the influence of any sunscreen. The control group should be as similar as possible to the other groups in the experiment, and all other variables should be kept constant. In this case, the control group would be a glass panel placed in the same location in the sun for the same amount of time as the other panels.