What Sunscreen Works

What Sunscreen really works?
Problem: Will sunscreen with an SPF of 4 be able to withstand the sunlight more effectively than SPF 45?
Purpose: Due to the increasing amount of sun exposure on teens, we want to ensure that sunscreen can protect against the sun. An increase amount of exposure can damage the skin directly. The dangers of increased sun can lead to the 3 types of skin cancer (Basal, Melanoma, and Squamous) and these types can spread to other parts of the body. The most dangerous form of skin cancer is Melanoma cancer and is developed from melanocytes. Melanoma is more likely to spread and it usually occurs on the chest and back. Basal and Squamous are the most common and develop from keratinocytes. There are several ways that this can be prevented and sunscreen is one of the most common forms of prevention.
Sun Protection Factors also known as SPF is used to measure the amount of protection against Ultraviolet B. SPF are the ratio it takes to determine the time the skin begins to redden and sunburn starts. This means that if sunburn starts at 15 minutes of exposure to the sun if you put on sunscreen with an SPF of 45 it is meant to protect you 45 times longer.
Research and Development: Shockingly, until recently, evidence that sunscreen prevented the deadly skin cancer melanoma was almost as thin as Gisele Budchen, a thin British model. That changed last year with the publication of a randomized controlled trial from Australia, in which study participants assigned to slap on sunscreen had less melanoma over 10 years. “Now, the evidence is there, and it’s very strong,” Dr. Wang says.
Still, it’s unclear what’s actually happening on the beach. In a study published last year in Cancer Causes & Control, people who said they used sunscreen actually reported more sunburns—bright-red risk factors for cancer. “Often people wearing sunscreen end up spending longer in the sun. If they don’t apply often enough, thickly enough, and to all of the exposed areas, they don’t get the protection they think they’re getting,” says study author Eleni Linos, M.D., a dermatologist at the University of California-San Francisco. For all the uproar, dermatologists and public health advocates agree sunscreen is an important weapon in your cancer-prevention arsenal.
Hypothesis: If sunscreen has an SPF of 45 it should be able to withhold ultraviolet rays from the sun more effectively than a sunscreen with SPF of 4.

Equipment: * Sunscreen with SPF of 4 and 50 * Agar Plates * Inoculating loop * Yeast Extract-Dextrose * Mutant Yeast Strain * Proper PPE * Balance * Weight boat * Incubator * Sun exposure
Procedure:
1. Gather all equipment and put on proper PPE. 2. Streak 3 agar plates with mutant yeast 3. Streak 3 plates with wild yeast 4. Cover all 6 plates with saran wrap 5. Measure .5 grams of SPF 5 sunscreen on two weigh boats 6. Measure .5 grams of SPF 50 sunscreen on two weigh boats 7. Use finger to rub SPF 5 sunscreen on plate with mutant yeast 8. Repeat step 7 on plate with wild yeast 9. Use finger to run SPF 50 sunscreen on plate with mutant yeast 10. Repeat step 9 on plate with wild yeast 11. Cover half of each plate with aluminum foil (including control plates) 12. Expose plates to sunlight for 30 minutes. 13. Take plates out of sunlight and uncover the plastic wrap and foil. 14. Place lids on top of the agar plates. 15. Place the agar plates in an incubator overnight.
Day Two: 1. Take the plates out of the incubator and analyze them. 2. Make sure that your controls are correct. 3. If your controls are not correct then the test is non valid and you must start over. 4. If your controls are correct look at the difference between the products that you tested and your conclusions. Agar plates: | Growth(foil) | Growth | Control Mutant | X | No | Control Wild | X | X | Wild Spf 4 | X | X | Wild Spf 50 | X | X | Mutant Spf 4 | X | No | Mutant Spf 50 | X | No |
This plate is the mutant control. The side that has no growth was the side that was exposed to sunlight for 30 minutes. It did not have any sunscreen protection.

This plate is the Mutant plate that had the spf 4 sunscreen on it. This plate was not streaked correctly so it is hard to tell if the sunscreen actually worked or not.

This plate is the Mutant that had the spf 45 sunscreen on it. This plate shows that the side that was exposed to the sunlight has less growth than the side that was covered with foil.

This plate is the Wild control plate. This plate shows less growth on the side with the foil but the growth is still there. So the sunlight slowed down the growth process but not enough to make it stop growing.