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Science · Drill 25

Science practice 25

10 questions ~9 min recommended
⏱ 00:00
Score
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Pair A Pair B Pair C Pair D Pair E Clear plastic
Approx. Retail Cost of Glasses ($) 10 350 25 90 n/a
UVB Reading Before Shielding (mW/m²) 742.3 742.3 742.3 742.3 742.3 742.3
UVB Reading After Shielding (mW/m²) 2.7 3.2 4.2 3.5 2.1 423.1
Shielding (%) 99.6 99.6 99.4 99.5 99.7 43.0
Description Dark tanning Waterproof Sport Oil-free Baby
SPF 4 8 15 30 50
UVB Reading with Sunscreen (mW/m²) 72.1 35.6 20.2 19.8 18.5
UVB Reading without Sunscreen (mW/m²) 742.3 742.3 742.3 742.3 742.3
Cost per Bottle of Sunscreen ($) 8.99 4.99 7.99 15.99 10.99

The sun is a source of many wavelengths of radiation that reach the earth. The earth's atmosphere absorbs some of these wavelengths, while others are able to penetrate and reach the planet's surface. Ultraviolet radiation from the sun comes in three different categories based on wavelength and penetration: UVA, UVB, and UVC.

UVB radiation has wavelengths of 280 to 320 nm and is partially absorbed by the earth's ozone layer. The UVB rays that do reach the surface can be absorbed by human skin and have been known to cause sunburn and many forms of skin cancer. Many products, from glasses to sunscreen, have been created to help protect humans from UVB radiation. Two groups of students set out to test the ability of materials to block UVB light, using a computer and a sensor specifically designed to detect UVB radiation.

Group 1

The members of Group 1 placed a sensor in full sunlight and shielded the sensor with a variety of sunglasses claiming to offer UVB protection. A reading was taken on the UVB sensor for each product, and the data were recorded in Table 8.1.

TABLE 8.1

Group 2

The members of Group 2 placed a sensor in the sun and shielded that sensor with a piece of glass. They tested sunscreens of increasing SPF (sun protection factor) on the glass, and the data were recorded in Table 8.2.

TABLE 8.2

1. In Group 2's experiment, SPF is the independent variable being manipulated and UVB is the dependent variable being measured. Which of the following graphs best represents the relationship between the SPF and UVB data from this experiment?

2. Which of the following questions could the students in Group 2 be attempting to answer using the data from their experiment?

3. According to the findings of Group 1:

4. Assuming that the sunscreen being tested was purchased in 10-oz bottles, which sunscreen had the best cost for the amount of UVB protection (use the formula $/mW/m2 of UVB blocked)?

5. Which of the following is MOST likely to represent a control that would have been used to ensure reliability of data in the experiment done by Group 2?

6. According to the results of Group 1's experiment, what percentage of UVB rays would a $200 pair of sunglasses block?

7. Based on the results of Group 2's experiment, what would the UVB reading most likely be if SPF 60 sunscreen were to be tested?

8. Which of the following is the experimental variable that Group 1 manipulated?

9. Which of the following implies the correct relationship between SPF and UVB blockage?

10. What other experiment could the students in Group 2 conduct using the same equipment?

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