THE STUDY OF HOW UV LIGHT AFFECTS UV BEADS. Aesha Desai. Cary Academy ABSTRACT

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1 THE STUDY OF HOW UV LIGHT AFFECTS UV BEADS Aesha Desai Cary Academy ABSTRACT The purpose of this study is to see what happens to the light of UV beads when different items are used to block UV light. The introduction is about what UV light is, what the electromagnetic spectrum is and what is in sunglasses lens such as how many coatings, and how it is made. The method tells how each experiment was done and the amount of everything that was used. The results tell what happened the experiments were done and describes each graph. The sunglasses blocked the most amount of UV light and Saran Wrap blocked the least. INTRODUCTION UV light is often called black light. Ultraviolet radiation is invisible to the human eye, but when it falls on certain surfaces, it causes them to fluoresce, or emit visible light. Figure 1: This is picture of UV light tube also known as Black Light

2 This portion of electromagnetic spectrum adjacent to the short wavelength, or violet, end of the visible light range is called ultraviolet radiation. Ultraviolet radiation is produced from some high-temperature surfaces, such as the sun. The ultraviolet spectrum is usually divided into two regions: near, or soft, ultraviolet (near the visible spectrum). Ultraviolet radiation is produced by special fluorescent lamps to support plant growth; hard ultraviolet radiation is used to kill germs and bacteria in places where a hygienic environment is the key, and in certain foods. Ultraviolet radiation can produce direct and indirect effects on the human body. The direct effects are limited to the surface skin because the rays have low piercing power. Direct effects include sunburn, suntan, and advanced versions to heavier doses. Categorized in 3 categories: UVA, also known as black light which causes tanning. UVB which causes damage in the form of sunburn and UVC which is filtered out by the atmosphere and never reaches the Earth. 99% of the sun's UBB radiation at sea level is UVA. UVB causes most of the problems related to sun exposure-things like aging, wrinkles, and cancer-although research is increasingly implicating UVA as well. There are certain things called melanocytes in someone s skin which makes the skin a certain color. When UV light touches the skin, it changes the pigment of the skin which gives someone so called sun tan. When someone gets a sunburn, they are getting cellular damage from UV radiation. Ordinary light is a mixture of light of many different colors. A beam of sunlight passing through a prism fans out into a band of colors. At one end of this band is red, followed by orange, yellow, green, blue, and violet, each color blending into the next. That falls in visible light. This particular sequence is called the visible range of the electromagnetic spectrum because it is the only range of the spectrum that humans can see with the unaided eye. Visible light itself is only a small part of a much larger spectrum of electromagnetic radiation. Electromagnetic radiation also includes ultraviolet light as well as gamma rays, x rays, infrared radiation, radio waves, and microwaves.

3 Figure 2: This shows the electromagnetic spectrum The following sections discuss the different technologies currently in use on a sunglass: Tinting, Polarization, Photochromic lenses, Mirroring, Scratch-resistant coatings, Antireflective (AR) coatings, and UV coatings. For Tinting, the color of the tint in the lens determines the parts of the light spectrum that the lens absorbs. Manufacturers use different colors to produce specific results. Many manufacturers use a process called constant density to tint the lenses. It s a very old method of creating sunglasses, and it produces a glass or polycarbonate mixture that has a uniform color throughout. Using this method the tint is build right into the lenses when they are created. The most common method for tinting polycarbonate lenses is to immerse the lenses in a special liquid that contains the tinting material. During Polarization, polarized filters are most commonly made of a chemical film applied to a transparent plastic or glass surface. The chemical compound used is typically composed of molecules that naturally align in parallel to one another. Photochromic lenses are usually sunglasses or prescription eyeglasses that darken when exposed to the sun. The can also be called photochromatic. Photochromic lenses have millions of molecules of substances such as silver chloride or silver halide, embedded in them. The molecules are transparent to visible light in the absence of UB light, which is the normal makeup of artificial lighting. But when they are exposed to UV rays in sunlight the molecules undergo a chemical change. The new molecular structure absorbs portions of the visible light, causing the

4 lenses to darken. The number of molecules that change varies with the intensity of the UV light. In Mirroring, the lenses in mirrored sunglasses have a reflective coating applied in a very thin sparse layer-so thin that it's half-silvered surface. Often the mirror coating is applied as a gradient that gradually changes shades from top to bottom. This provides additional protection from light that comes from above while allowing more light to come in from below or straight ahead. That means that if someone is driving, the sun's rays are blocked but the someone who is driving can see the dashboard. Sometimes the coating is bigradient, shading from mirrored at the top and bottom to clear in the middle. For Scratch-Resistant Coatings, glass is naturally scratch resistant, but most plastics are not. To compensate, manufacturers have developed a variety of ways to apply optically clear hard films to a lens. Films are made of materials such as diamond-like carbon and polycrystalline diamond. Through a process of ionization a thin but extremely durable film is created on the surface of a lens. AR Coatings are a common problem. On Tori Banks from Cary Academy s second experiment, Tori studied the brightness of UV beads by putting different amounts of SPF on them. This graph shows that the higher the SPF the lower the color intensity. The difference of the color intensity between 0 and 30 SPF wasn t as big of a difference. This happened because the 15 SPF showed that there was no difference between them. The results show that the chemical substance in the sunscreen in 15 SPF didn t have a difference of when there was none. On Tori Banks from Cary Academy s fourth experiment, Tori studied the brightness of UV beads outside by seeing if it was cloudy or sunny outside. This experiment was to see if the sunlight outside was the same as the UV light. A UV light was raised at different cm to see if it affects the color of the beads. The beads were lied down on the table with 100 SPF, and then the UV light was shined on them to see its color intensity. This experiment was performed by doing the same first experiment just in a cloudy day.

5 Tori figured out that even though the bead was raised 1cm off the ground to 4cm off the ground, in sunny days, the bead is brighter than in cloudy days. MATERIALS AND METHODS The materials that were used were UV beads, a UV light, saran wrap, tissue papers, sunglasses, water, a glass beaker, and tape. For the first experiment, a UV light bead was put in right in front of the UV light for 1 min. It was put at 0 cm away. After that, it was placed on a piece of paper that had the UV light scale on it from Then the amount of light was measured on the scale. This process was repeated 3 times. After doing the first distance 3 times, the number was averaged to get an exact measurement. Then the UV bead was moved back 2 cm. Each time the numbers were averaged, the UV bead was moved back 2 cm until it was at 10 cm. For this experiment, a UV bead was put right in front of a UV light for 1 min. First it was put only 0 cm away. After that, it was placed on a piece of paper that had the UV bead s intensity scale on it and was measured. This process was repeated 3 times then averaged to get an exact measurement. The UV bead was then placed in front of saran wrap, tissues and sunglasses. The saran wrap and tissues were taped down on the table so that the average would be more exact. Figure 3: This picture shows the UV light being shown on the sunglasses with the UV beads behind it.

6 For this experiment, a UV bead was put in front of different amounts of tissue paper for 1 min. The first thing that was done was one tissue was taped down on the table. A stool was placed underneath it to hold the bead and the UV light. The UV light was placed on the back of the tissue to hold it still and the bead was placed on the outside so it could be exposed to the light. The beads were then placed on the intensity scale to measure how much light is in them. This was done 3 times to get an exact measurement. This experiment was done with 1 tissue, 2 tissues, 3 tissues and 4 tissues. In this experiment, a UV bead was placed in water for different amounts of time. The first time the bead was not put in any water. It was placed in front of the UV light and then was measured for how bright the bead was by putting it on the paper scale for the light intensity. This was done 3 times to get an exact measurement. This experiment was then done for 10 sec in water, 20 sec in water and 30 sec in water. In this experiment, a UV bead was placed in front of a glass beaker for different amounts of time. A beaker was placed in front of the UV light. Then the bead was placed on the other side of the beaker so that the UV light could go through the beaker to get to the bead. It was first done for 10 sec. The bead was then placed on the scale that shows different intensities of UV light. This experiment was then done with 20 sec, 30 sec, 40 sec, 50 sec, and then for 60 sec. RESULTS & DISCUSSION The results below show that when the UV bead was closest to the UV light, it was the brightest. When it was 10 cm away from the UV light, it had less light in it. The further away the bead was from the light, the darker it got. The highest was 10 and the lowest was 1.7. This shows that if someone is very close to the sun, the body is more exposed to the UV rays. When their skin is further away, it is less exposed to the UV rays so it is less likely to get a sunburn or a suntan. It was thought that this happened because when the body is further away from the sun, less UV rays come to the skin which causes an unlikely chance to get a sunburn.

7 Figure 4: This shows how bright the bead was when it was taken further and further away from the light. The results below show that without anything to block the UV light out, the bead was the brightest it could get. When Saran wrap was placed in front of the UV light, the light went right through it and it was also at the brightest it could get. The tissue could only block a little bit of UV light so it was, on the scale of 1-10, a 9.3. The sunglasses blocked most of the light and it was the object that made the UV bead have the least light out of all the other objects. On a scale of 1-10, it was a 1.3. This was thought to have happened because the darker the item is, the more layers it has and the less light goes through it.

8 Figure 5: This graph shows how bright the beads were in front of different materials. The results below show that with one tissue the UV light went all the way through. It was at the brightest it could get. When more tissues were added on the paper, the UV bead got dimmer. The lowest was when there were 4 layers of tissues. On a scale of 1-10 it was 0.3. This shows that if someone wears 4 layers of tissues all over their body at the beach, it is less likely that their skin would get sunburned. This was thought to have happened because the more layers of something that is put on someone s body the less likely it is to get a sunburn. Figure 6: This shows how bright the beads were in front of different layers of tissues.

9 The results below show that no matter how long someone stays in water, it doesn t block the sun from the body. The graph below shows that when the bead was put in water for different amounts of time and then put in front of a UV light, on a scale of 1-10, it was a 10 for the whole time. The reason that happened was the water drips off the bead. It doesn t just stay on the whole time. Figure 7: This shows how bright the beads were when placed in water for different amounts of time. The results below show that when the UV bead was in front of the glass beaker for 10 and 20 sec, it was the least bright out of all the other times. On a scale of 1-10, both beads were 6. When the bead was in front of the glass beaker for 50 and 60 sec, it was at the brightest then all the other beads. It was also at the brightest it could get. On a scale of 1-10, it was both beads were 10. The data has a certain pattern in it. It looks like stairs. It goes by twos. It was 6, 6, 8, 8, 10, and 10. This graph shows that the longer someone stays in front of glass, the more sunburned their skin could get. This was thought to have happened because when the bead was placed in front of the glass

10 beaker for more amounts of time, the more it is exposed to the light. The more someone is exposed to light, the more likely their skin is going to get sunburned. Figure 8: This graph shows how bright the beads were in front of the glass beaker for different amounts of time. CONCLUSION The results show that sunglasses block the most UV light out of all the items used. The reason that the results are important is because without them, anyone who did the experiment would not know what the last person got. The overall hypothesis was incorrect because it was thought that most of the items used would block most all UV light but a lot of them did not block so much. A future follow experiment would be taking different types of sunscreen and putting it on the bead.

11 Banks, Tori. The Study of How Sunscreen Affects UV Beads. Cary Academy Print. Brain, Marshall. How Stuff Work. New York, NY. Hungry Minds Print. "ultraviolet radiation." Compton's by Britannica. Encyclopædia Britannica Online School Edition. Encyclopædia Britannica, Inc., Web. 13 Jan Wikipedia contributors. "Ultraviolet." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 13 Feb Web. 14 Feb "UV, Or Not UV? - Technique - NAILS Magazine." NAILS Magazine : Dedicated To The Success Of Nail Professionals. Web. 15 Feb