Exploring Ultraviolet (UV) light from the Sun

Transcription

1 Public Outreach - Make and Take Activities What You ll Need UV detectors a.k.a. UV beads. These can be ordered inexpensively from container or covering to prevent the Sun from hitting the detectors prior to the activity. (Black film canisters work very well, so does a closed fist or a pocket!) a cup with water sunscreen and a zip-lock bag sunglasses Sun and shade (When doing this activity indoor, you can use a UV lightbulb / blacklight or an opened sunny window the glass in the window might block out most of the UV rays!) (optional) pipecleaners or strings to hold the UV detectors if distributing beads to participants to take away. (We suggest our participants to hang the beads from a purse or shoelace to continue detecting UV wherever they go.) Exploring Ultraviolet (UV) light from the Sun About this Activity The Sun gives off different kinds of energy: including heat, visible light, and invisible light in the form of ultraviolet (UV) rays. While the Earth s atmosphere protects us from most of the Sun s harmful UV rays, there is still an abundance of UV rays around us. This activity explores UV rays from the Sun and ways we can protect ourselves from these potentially harmful UV rays. Left: Comparing UV detectors with and without the covering of a pair of eye-glasses. Below Right: Examples of materials that can be used for this activity. Preparation Set up 5 stations: a sunny spot, a shady spot, sunglasses, a cup with water, and sunscreen. For the sunscreen station, squeeze a little sunscreen into the zip-lock bag and drop in a bead (this keeps sunscreen from getting all over.) If doing this activity indoor, use an opened sunny window (the glass in the window might block out most of the UV) or use a UV lightbulb / blacklight to imitate the Sun. To Do and Notice 1) Explain that you have detectors (UV beads) which turn color when they are exposed to UV rays. The beads detect the ultraviolet coming from the Sun and the more UV there is, the darker the beads become. We prefer using beads in only one color and in a deeper color, like purple, to make the color changes and comparisons more obvious. 2) Ask participants to make predictions. Some questions to consider: Where do you think the bead will turn the darkest? What happens in the water? Do sun glasses protect eyes from UV? What about regular glasses? What do you think happens to UV on a cloudy day? Is the shade really free of UV? 3) Demonstrate or ask the participants to try out the UV detectors at different stations. 4) Ask your participants if there are other conditions that they think will block UV. They may want to test out other materials that they have on hand, such as clothing and regular glasses. 5) The beads will turn back to the original color when no longer exposed to UV. Give away UV detectors so participants can attach them to their jackets or purses to continue detecting UV! Activity Notes This activity demonstrates that different materials will block UV rays to different extends. When proper Sun protection is not used, UV can damage our skin and eyes. To learn more about UV, other forms of energy emitted by the Sun, or how UV affects our skin, follow the links under Related Websites below. Related Websites NASA s Imagine the Universe: Electromagnetic Spectrum American Academy of Dermatology: UV Index

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3 UV Thing The Sun produces different types of light. Many of the types of light are invisible to us. One of those is ultraviolet light, or UV. We need UV light because our skin uses it to manufacture vitamin D, which is vital to maintaining healthy bones. But we only need about 10 minutes of sunlight each day to allow our skin to make the amount of vitamin D we need. Too much exposure to UV causes sunburn and leads to wrinkles, skin cancer, and cataracts. The good news: we can protect ourselves by covering ourselves by covering up with clothing and using Sun block. In this activity, you and your child are going to experiment to find out what happens when the UV-sensitive beads are exposed to different sources of energy: visible light from flashlight, heat from a hair dryer, ultraviolet light from a UV lamp, and sunlight. What You Need: What to Do: Four UV beads A few non-uv beads Pipe cleaners Flashlight UV light Hair dryer Invite your child can make a pipe cleaner animal or person or piece of jewelry; thread 4 UV beads and non-uv beads onto the object, alternating the types of beads Make predictions about the reaction of the UV beads to the flashlight, hair dryer and UV light Using the flashlight, shine it on the object Do your UV beads change colors? Using the hair dryer, blow the object Does the heat cause the UV beads to change colors? Using the UV light, shine it on the object Do your UV beads change colors? Cover your object with your hand and take it outside to a shady spot Predict whether your object will change colors in the shade. What about in the full sunlight? Now uncover your object in the shade Was your prediction right? Put your object in the Sun What happens? Are there any changes? Copyright by the Lunar and Planetary Institute, 2009 LPI Contribution Number

4 Parent Prompts: If heat and light from the flashlight don t change the color of the UV beads, then what does? (ultraviolet, or UV, light) Does the Sun give off invisible ultraviolet (UV) light? How can you tell? (the beads turn colors!) How does ultraviolet light affect us? Note: The UV-sensitive beads used in this experiment serve as UV radiation detectors. They contain a pigment that changes color when exposed to UV light from the Sun or from blacklights. The intensity of the color corresponds to the intensity of the UV light. When shielded from UV sources, or when exposed to light that does not contain UV such as indoor light bulbs the beads remain white. The beads are designed for multiple use and, according to the manufacturers, will change color up to 50,000 times. Copyright by the Lunar and Planetary Institute, 2009 LPI Contribution Number

5 Color Changing UV Beads Learn how ultraviolet radiation from the sun can damage your skin and how you can protect yourself. People of all races can burn, and having a tan is a sign that your skin has been damaged by ultraviolet (UV) radiation, which comes from sunlight and tanning booths. Exposure to UV radiation is the major risk factor for skin cancer. Stay Safe in the Sun Protect yourself from UV radiation in the following ways: Seek shade during peak sun hours (10 am to 4 pm). Cover up. When outdoors, wear a long-sleeved shirt and pants, a hat to shade the ears, face, and eyes, and sunglasses to protect the skin around the eyes. Use a sunscreen with a sun protection factor (SPF) of 30 or higher and reapply often. The higher the SPF, the better. Check the UV index, which predicts the next day s ultraviolet radiation levels on a scale, to help you plan sun-safe activities. To find out the UV Index for your area, visit the EPA SunWise UV Index website at Avoid tanning beds, which can lead to skin cancer and premature aging of the skin. UV Beads Experiments Test how the above actions can protect you from the damaging effects of UV radiation. UV beads have a chemical substance embedded into the plastic that will change color when exposed to UV radiation (sunlight). The beads will remain white indoors as long as they are kept away from windows or doors where UV light can leak into the room. Shade Test -- Take your beads outside and stand in the shade. Do they change colors? Now, move the beads into the sun and note what happens. Sun Screen Test -- With all of the SPF (Sun Protection Factor) numbers available, we want to know what SPF lotion really works best at keeping out the sun's harmful UV rays? Start by collecting various strengths of sunscreen (SPF 4, 15 and 50, for example). Since the UV Color-Changing Beads are very sensitive to changes in UV energy, you can use the beads to determine the blocking potential of the sunscreen. Place the beads in a zipper-lock bag and apply a layer of sunscreen to the outside of the bag. Use a permanent marker to write the SPF number of the sunscreen you're testing on the outside of the bag. Be sure to set-up one bag without any sunscreen coating for comparison purposes. Expose the beads to direct sunlight for 5 minutes and look for any changes in color. The beads will always change color regardless of how good the sunscreen blocks UV - the beads are very sensitive! The key is to rate the color of the beads on a scale of 1-5,

6 with 5 showing the most color or "burning" and 1 showing the least color. The bag without any sunscreen is an automatic "5". You can also test the difference between new and old sun screen. Sunscreen manufacturers suggest that you throw away old sun screen because it does not block out harmful UV light. Do your tests support this claim? Here's what others discovered... SPF 4 did not do well at all while SPF 30 was the best blocker and received the best rating of 1. Cloudy Day -- Test to see if the beads change color on a cloudy day. If they change color, then you can see why doctors warn people to wear sunscreen even on a cloudy day. Observe how well the beads change color when exposed to sun light at different times of the day. According to your data, what time of day does the sun give off its most intense UV light? Protective Clothing and Sunglasses -- Test the ability of your sunglasses to block out ultraviolet light by covering a few beads with the lens of your sunglasses. If the beads do not change color, your sunglasses block out harmful ultraviolet light from your eyes. If not, you paid too much for that UV coating! You can also do the same thing by placing the beads under different fabrics and see what happens. How do UV beads work? The UV beads contain different pigments that change color when exposed to ultraviolet light from any source including the sun. UV light is invisible to the naked eye. Therefore, UV beads help to detect when UV light is present. Each bead will change color about 50,000 times before the pigment will no longer respond to UV light. When you expose bare skin to sunlight, your skin will either burn or tan (which doctors warn is still not healthy for your body). UV radiation wavelengths are short enough to break chemical bonds in your skin tissue and with over prolonged exposure, your skin may wrinkle or skin cancer may appear. These responses by your skin are a signal that the cells under your skin are being assaulted by UV radiation. Seek shade! Cover up! Wear sunscreen! August 2008 Parts of this are adapted from

7 Ultraviolet Testing with Color Changing UV Beads Experiments Steve of 2 5/1/2014 8:44 AM

8 Ultraviolet Testing with Color Changing UV Beads Experiments Steve of 2 5/1/2014 8:44 AM

9 UV DETECTING BEADS EXPERIMENT Asking simple questions, Designing simple experiments References Exploring UV Light from the Sun, NASA, Online. Color Changing UV Beads, Steve Spangler, Online. Go to Ms. Barlos s Links and select Scientific Method Lab Template Materials -UV detecting beads (from Ms. Barlos) Some other supplies you may need, depending on your experiment design: -Paper plates -Various sunscreen lotions (differing SPF, ages, brands) -Small clear baggies -Cotton balls for applying sunscreen onto baggies -Dark lightweight towels to serve as coverings -Various sun hats -Various sunglasses Background Ultraviolet ( UV ) light is one of the invisible frequencies of light that is given off by the sun. Over exposure to it can be harmful to many things including humans. Its effects can be seen in faded paper, a sunburn, and a cracked rubber hose that has been left out in the sun. UV-sensitive beads contain a pigment, which changes color when exposed to ultraviolet light from the Sun or other UV source. The pony beads are not, however, affected by visible light and so will remain pale indoors, or when shielded from UV light as is the case in most modern automobiles. All beads are pale, off-white in the absence of UV light. The ultraviolet beads will cycle back and forth (to bright colors and back again) over 50,000 times! Questions to Investigate: 1. What kinds of light contain UV? Expose the beads to light from different sources, including the sun, incandescent light bulbs, fluorescent light bulbs, 2. Can you get sunburned on a cloudy day? Can you get sunburned in the shade? 3. How effective are different sunscreens? Place beads in clear baggies, coat the baggie with a sunscreen, and compare the rate of color change. 4. Can UV pass through window glass? Try different types of glass, including tinted glass and car windows. 5. How much UV protection do different types of sunglasses provide? 6. How does the amount of UV from the sun compare to the UV in tanning booths? Now Design a Simple Experiment:

10 1. Decide what UV protection you will test. Try COMPARING 2 different types of protection. 2. Decide how to SET UP the experiment. What is your control set up? Draw a sketch of your experiment on notebook paper 3. Decide how to QUANTIFY your results? HINT: rank the intensity of the various colored beads on the bracelets. 0 = Bead did not change color (remained white) 1 = Very Pale/Light 3 = Medium 5 = Medium/Dark 9 = Very Dark For example, if the bead has a very light blue color, write the number 1 in the appropriate column. 4. Keep track of your results in a DATA TABLE (see sample below) in your notebook. 5. What conclusion can you draw from your experiment? Try graphing your conclusion.

11 UV Beads From Stevespanglerscience.com: UV Beads have a chemical substance embedded into the plastic that will change color when exposed to UV radiation (sun light). The beads will remain white indoors as long as they are kept away from windows or doors where UV light can leak into the room. Materials Color changing UV beads Zipper-lock bags String Different types of sunscreens Newspaper to cover the table and/or paper plates Fluorescent light source Sunglasses Some experiments to try Sun Screen Test With all of the SPF (Sun Protection Factor) numbers available, we want to know what SPF lotion really works best at keeping out the sun's harmful UV rays? Start by collecting various strengths of sunscreen (SPF 4, 15 and 50, for example). Since the UV Color-Changing Beads are very sensitive to changes in UV energy, you can use the beads to determine the blocking potential of the sunscreen. Place the beads in a zipper-lock bag and apply a layer of sunscreen to the outside of the bag. Use a permanent marker to write the SPF number of the sunscreen you're testing on the outside of the bag. Be sure to set-up one bag without any sunscreen coating for comparison purposes. Expose the beads to direct sunlight for 5 minutes and look for any changes in color. The beads will always change color regardless of how good the sunscreen blocks UV - the beads are very sensitive! The key is to rate the color of the beads on a scale of 1-5, with 5 showing the most color or "burning" and 1 showing the least color. The bag without any sunscreen is an automatic "5". You can also test the difference between new and old sun screen. Sunscreen manufacturers suggest that you throw away old sun screen because it does not block out harmful UV light. Do your tests support this claim? Light Test

12 Place a handful of UV beads near a fluorescent light. Do any of the beads change color? Can you get a sun burn or a tan by sitting next to a fluorescent light? Black Light "Black light" (long wave ultraviolet light) can also be used to change the color of the beads. You can purchase a black light at many specialty stores or hardware stores that have a large section of light bulbs. Steve Spangler Science also sells them. Sometimes those high intensity lights (mercury vapor) found in a gymnasium emit just enough UV light to make the beads barely change color. Sunglasses Test the ability of your sunglasses to block out ultraviolet light by covering a few beads with the lens of your sunglasses. If the beads do not change color, your sunglasses block out harmful ultraviolet light from your eyes. If not, you paid too much for that UV coating! Potential problems with this experiment: Give kids a bottle of sunscreen and ask them to spread it on a plastic bag and chances are there will be sunscreen all over the table and windowsills when they are done! You could use newspaper to cover the tables and/or bring paper plates that the kids can put their bags on to avoid a mess. This should save time on clean up as well. Kids may decide it d be fun to take the beads out of the bags and throw them around! You could tell kids ahead of time that if they keep the beads in the bag for the experiment, then they can take them out and make a bracelet using the string afterwards. Warn students that if they throw beads, they won t be able to keep them in the end. Letting them keep the beads on a bracelet also reduces the chances that they will scatter the beads all over the floor between the time you leave and the time they go home. The kids may all want to use the best (highest SPF) sunscreen for their beads, which may lead to sharing problems and weaken the overall variance you will see in UV protection from the sunscreens. Avoid this problem by writing an SPF on each of the bags with a sharpie, and distributing the bags randomly to the kids. Then tell the kids to use the sunscreen with the SPF that matches the number on their bag. Kids that have the control, no sunscreen bags may lose interest when watching their peers put sunscreen on their bags. Let all of the kids put sunscreen of some sort on their bags and bring an extra control bag. Have a backup activity in case you don t see a lot of change in the beads or be prepared to go outside to see the changes happen.

13 HOPE Partnership Supported by a Science Education Partnership Award (SEPA) from the National Center for Research Resources, National Institutes of Health (Grant No. R25 RR018490) UV BEAD COMMUNITY EVENT Abstract The purpose of this activity is to inform the general public about protecting themselves, along with their children and/or pets, from UV radiation. This activity can be used at community events in conjunction with the Research Advances presentation or at a health fair. Objectives By the end of this activity, participants should be able to: Understand the effects of UV radiation exposure from sunlight; Identify how to protect themselves and their children and/or pets from UV radiation; and Visually explore the effects of UV radiation. Background Skin cancer is a growing problem in the United States. In 2007, over 1 million people have been diagnosed with skin cancer. The two major types of cancer include nonmelanoma and melanoma. Nonmelanoma is more commonly occurring in the United States and about 95% of cases are curable. Melanoma is a more serious form of cancer. Although not as common as nonmelanoma, melanoma can be very aggressive and spread throughout the body. The most common cause of skin cancer is UV radiation. Sources of UV radiation include the sun, sunlamps and tanning beds/booths. Time Preparation Time Materials Preparation 30 minutes 5 minutes UV detecting beads. These can be bought at teacher supply stores or online, search for UV beads. String or cable ties UV bead handout Purchase beads and string prior to event. Prepare materials, review the fact sheets and other materials Activity 1. Tell participants they will be doing an activity regarding the detection of UV radiation. UV radiation cannot be seen, so this bracelet will help participants know when they are being exposed. 2. Participants can make a bracelet from the UV beads and the string. Tell them about UV radiation and skin cancer. When the beads change color, it is a good reminder to put on sunscreen or do other things to protect yourself from the UV rays. CC HOP (02/08) Tab 7 Page 59 Hands-on Activities

14 HOPE Partnership Supported by a Science Education Partnership Award (SEPA) from the National Center for Research Resources, National Institutes of Health (Grant No. R25 RR018490) UV BEAD COMMUNITY EVENT Color Changing UV Beads Become an ultraviolet detective with these amazing UV-sensitive beads! It's solar magic in action! Make bracelets, test the effectiveness of sunscreen, or experiment with color while you learn about the power of sunlight. Included is a science activity guide with lots of fun experiments with solar radiation and light. How It Works: UV sensitive beads have a chemical substance embedded into the plastic that will change color when exposed to UV radiation from the sun. The beads will remain white indoors as long as they are shielded from sunlight and kept away from windows or doors where UV light can "leak" into the room. The energy beads are not affected by light from light bulbs that do not emit ultraviolet light. Don't blink your eyes because our color-changing beads have a new formulation that makes the beads more reactive to the sun and the colors more vibrant. The solar-active pigment keeps the beads from permanently discoloring and speeds up the time it takes for the beads to change back to their original white color. What Does It Teach? Use the beads to teach kids about the ultraviolet radiation and the care that needs to be taken to prevent the damage it may cause. Ultraviolet (UV) light is the invisible radiation that will give you a sunburn and injure your eyes if you're not careful. Sunglasses and sunscreens absorb UV photons. You can test their protective qualities by using your UV detecting beads. Experiments To Try: Test your sunglasses by placing them in the sunlight and covering a few of the energy beads with the lenses. If the beads remain white, then your sunglasses are blocking harmful ultraviolet rays. Test the effectiveness of your sunscreen by coating a few of the beads and placing them in the sunlight. If they change color, better buy some more cream! Manufacturers suggest that you throw away sunscreen that is over a year old because it loses its effectiveness. Test a variety of plastic bottles and transparent containers to see which ones block out the UV rays the best. Some brown prescription bottles have labels that read UV BLOCKING PLASTIC because many drugs are sensitive to damaging UV light, so the bottle is specially designed to preserve the life of prescription medicines. Test whether UV radiation can penetrate through car windows. Is it possible to get a sunburn if your car windows are rolled up? CC HOP (02/08) Tab 7 Page 60 Hands-on Activities