For my project, I tested the effectiveness of sunscreen on the skin. The sun emits ultraviolet (UV) light, which is invisible to the eyes and has higher energy than visible light. Long exposure to UV radiation can cause the skin to get sunburn. I used sun protection factor (SPF) 50 aerosol and lotion in contrast to an unprotected surface. I used these sunscreens on various colored construction papers to test and see the barrier of the unscreen against the paper to see what it would look like on human skin. Then observing the UV forecast for the day in my area and placed the paper swatches in direct sunlight at peak UV levels. The results were that the SPF 50 lotion had a thick barrier still after four hours of direct sunlight and after the fourth hour, there were orange burnt detections on the pink, brown, white, and orange paper. As for the SPF 50 aerosol, it gave even distributed sun protection over the constitution paper. Resulting in little to no color change on the construction papers. Lastly, the control group of the unprotected. After leaving the construction paper outside in direct sunlight with no protector the colors on each paper faded into a lighter shade than the SPF swatched papers.

UV rays can cause damage to the skin and the barrier function. The use of sunscreen can prevent damage from UV radiation. In “Efficacy of Ceramide-Containing Sunscreen on Skin Barrier” the writers of the Journal of Cosmetic Dermatology said; that UV radiation can induce reactive oxygen species that can disrupt the balance of oxidative and anti-oxidative systems in the skin. An abundance of reactive oxygen species in the skin can cause oxidative damage to biomacromolecules such as nucleic acids, lipids, and proteins inside skin cells. The skin relies on melanocytes’s melanin to absorb UV energy and protect against photo-damage. While the stratum corneum, known as a brick-and-mortar structure acts as the first barrier directly to UV radiation. Moderate exposure to UV radiation can enhance the skin barrier function, but a cute overexposure can damage to skin barrier, resulting in symptoms such as erythema, edema, blisters, and inflammatory pain.

The stratum corneum is the skin tissue that is the main protective barrier of the body that protects against microbial attacks and moisture loss. Protecting this tissue is crucial against ultraviolet exposure with sunscreen. In “Screening Sunscreens” the writers at the Journal of Cosmetic Science said “The properties of the stratum corneum were measured before and after UV exposure, both with and without sunscreens applied, to determine the role of sunscreen in preserving the barrier function of stratum corneum. Without the usage of sunscreen on our skin we can cause UV radiation damage to our stratum
corneum tissues. With the use of sunscreen, we could eliminate the imbalance of the oxidative system in the skin. Without a sun protector overexposure to UV radiation can be departmental and very painful. Daily use of sunscreen can protect the skin barrier and increase hydration with the decreased factors of redness.

Reference Cited
Title:Efficacy of ceramide‐containing sunscreen on skin barrier. By: Cao, Yu, Zhang, Xianghua,
He, Xiaofeng, Wang, Wenna, Yi, Yi, Ai, Yunfei, Journal of Cosmetic Dermatology, 14732130,
Feb2024, Vol. 23, Issue 2Database: Academic Search Premier
Title: Screening sunscreens: protecting the biomechanical barrier function of skin from solar
ultraviolet radiation damage. By: Berkey, C., Biniek, K., Dauskardt, R. H., International Journal
of Cosmetic Science, 01425463, Jun2017, Vol. 39, Issue 3Database: Academic Search Premier
Corp., Pelmorex. “UV Report.” The Weather Network. Accessed June 20, 2024. https://
Team, Children’s Museum. “SPF Science Experiment.” Children’s Museum of Sonoma County,
November 15, 2021.