Hi! This is my Science Project Blog about UV rays, skin cancer, tests and more. BUT, before you start reading it, I made this animoto of pictures about sunsets and rises. You know...to get in the mood of things around here :)



P.S. It doesn't look too good at full size but if you want to see a picture closer up, just press the pause button at the bottom.
P.P.S. I also made the "welcome" sign above!

P.P.P.S Also, don't forget to check out my other cool sci-blog "Colors in Colors" at http://www.sillyscienceqz.blogspot.com/

Question

I’ve realized that when I leave sunscreen outside or in a car, it develops a part oil/part sunscreen consistency. It makes me wonder if it’s any good because I burn really easily. Can sunscreen repel UV rays at the same level when it has been left in the heat to the point where its composition separates?

Background Info

UV light is part of the Electromagnetic Light Spectrum (see chart to side). The Electromagnetic Light Spectrum chart is used to describe the characteristics of the different types of light waves. All the waves on the spectrum travel at the speed of light but have their own wavelengths and frequencies. Visible light, or the part that we can see, is only a small section of the spectrum. The UV discovery fits into the Electromagnetic Light Spectrum just past the left side of visible light, next to color violet.

Increased values of UVA and UVB wavelengths reaching the surface have been known to produce damage on small plants and animals from overexposure. On humans this can cause Erythema, or sunburn. Erythema happens when the skin cells absorb too many UV rays. This causes the skin to send an increased amount of red blood cells to the area, creating a red appearance.

One of the worst effects of UV rays is called melanoma, also known as skin cancer. Any form of skin cancer is almost completely related to UV radiation. Skin cancer rates have been rising since the 1970’s and it is increasing now by 3% a year. It is predicted that one in every five Americans develop a form of skin cancer sometime in their life making melanoma the 6th most common cancer in the world. It is also proven that one American dies of skin cancer every hour. This is why I'm concerned about the effectiveness of suncreen that has been stored in high heat.

One way to reduce these affects is the use of sunscreen. Sunscreen is a lotion, spray, or gel that reflects or absorbs UV light. Sunscreen filters light in one of three ways: organic chemicals that absorb light, inorganic particles that reflect light, or organic particles that absorb and also reflect light. Sun Protection Factor (SPF) is the measure of the effectiveness of sunscreen. This means that with SPF 35, your skin would only burn if it was exposed to 35 times the amount of UV light it would normally take to get sunburned. Although, this can vary depending on your skin type, reapplication, etc.

UV beads are used to measure the amount of UV light based on their color. When in UV light, they react and turn blue. I created a scale from 0-7 to measure the sensitivity of the bead to UV light when coated with sunscreen. This scale runs from white to deep blue. If no UV light is absorbed, the bead will remain white and the rating would be a 0. If it is able to absorb all UV light, the bead would be dark blue and it would be rated a 7 on the scale. Please note that the scale is not a measure of the actual UV energy being absorbed by the beads, it is a measure of the relative sensitivity of the bead to UV light.

Separation of the sunscreen mixture could be caused by long exposure to heat. Heat is the energy in a substance and it can be potential or kinetic. When heat changes the kinetic energy of the molecules, the substance rises in temperature. Temperature is not a form of energy; it is a number used to measure it. If the substance is heated long enough it can change state (liquid to gas for example) or separate into its different ingredients.

Did you get all that? By doing this experiment and testing the effect of heat on sunscreen, it might be able to prevent other people (and me!) from further damage caused by UV rays.

Hypothesis

If sunscreen is heated repeatedly, then it becomes less effective in reflecting UV rays.

Procedure

Materials:
· One piece of black paper
· Silver Sharpie
· Black Sharpie
· One bottle of 55 SPF Neutrogena Sunscreen (lotion)

· 40 Color Changing Energy Beads (blue)
· Tinfoil
· Elmer's Glue
· Oven
· Timer
· 9" by 11" baking pan
· Paper towels
· Water
· 10 small paintbrushes
· 8 small glass bowls with lids
·tablespoon measure
· Sun
· Outdoor table
· UV Scale

Steps:
1) Put 1 tablespoon of Neutrogena Sunscreen into each of the 8 bowls and with the back of the tablespoon smooth out the clumps.
2) Cover each bowl completely with tinfoil and label each numerically 1-8 with the black Sharpie. Do Not take the covers off until the end!

3) Preheat oven to 170*F.
4) Use oven mitts on the following steps involving an oven.
5) Heat all 8 bowls for 6 hours and then take set bowl 1 aside.
6) Heat the remaining bowls for another 6 hours at the same temperature and take set bowl 2 aside.
7) Repeat this processes until all the bowls have been heated the amount of times that their number states.
8) Take the black paper and fold into 10 sections. Label each as shown and trace in silver Sharpie.

From left to right across the top and then left to right across the bottom it reads: No Sunscreen, No Days in Heat, 1 Day in Heat, 2 Days in Heat, 3 Days in Heat, 4 Days in Heat, 5 Days in Heat, 6 Days in Heat, 7 Days in Heat, and 8 Days in Heat.
9) Glue four beads onto the center of each section and let dry for a day.
10) Using a small paintbrush, apply sunscreen from each bowl and original Neutrogena bottle onto the corresponding beads glued on the paper. For example, paint beads in the "1 Day in Heat" box from bowl number 1. Coat the outside and inside of the beads with a uniform layer. Be sure to wash and dry paintbrush in between each coating with lukewarm water.

11) Wait a day for sunscreen to dry.
12) Take paper outside and look for results after 5 minutes.

Results

HURRAY!!!!! My experiment worked and I even uploaded this cool HD video that slowly zooms over my results. Look at the difference between 1 and 8 then look at the difference between 7 and 8 on the video. I think that's enough proof right there! Also, above each set of beads lie a regular uncoated bead to show you the difference between regular and sunscreen coated.

I've also made a graph that displays my results. As you can see, the amount of UV rays hitting the beads gradually goes up, especially from "None" to "8". The reason I did 1/2 steps on the scale is because it's pretty much imposible to make a scale on the internet with such tiny intervals. In fact, the one I made I had to do by hand on the color creater, they didn't even have them in the little easy-to-use color charts! Life is so hard. ;)

Conclusion

From the trends in the graph, it appears that the longer you heat sunscreen, the more UV rays it takes in. Using the Bead Sensitivity Scale that is based on the color of the bead as more UV light is apparent, it is shown that the color does increase as the sunscreen was heated more. Also, the sunscreen itself seemed to change when introduced to heat turning into a separation of sunscreen and oil. These results further increased to the point where number 8 was more jelly textured and yellow then smooth and white as normal sunscreen is. I sure don't want to put that on. My hypothesis stated that: if sunscreen is heated repetitively, then the less effective it will become in reflecting UV rays, was proven true when tested. The only variation in the experiment I found was that it is hard to apply the same amount of sunscreen for every bead. No other questions were presented. It would be suggested that all sunscreen be kept indoors and taken out of the car to prevent them from being spoiled or unusable. Or just gross to put on.