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Grades: 5-8
Author: Beth Kennedy
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Module Description
Participants explore Ultraviolet (UV) detecting beads and conduct several investigations with them to find sources of UV radiation and find sources that block UV radiation.
Review with participants that sunlight is a primary source of energy. The facilitator may also want to break sunlight or another light into the visible spectrum with a prism or a diffraction grating placed on an overhead projector. This will lead into the discussion of light that is not part of the visible spectrum, such as infrared and ultraviolet (UV) light. UV light is the invisible radiation that can give you a sunburn and injure your eyes/vision if you are not careful.
Engagement
If the participants have no prior knowledge of UV beads, make a UV detecting bracelet by stringing as many beads as desired on a piece of thick string, ribbon, yarn or a pipe cleaner. If using a pipe cleaner, tuck/wrap ends carefully around the band to prevent being poked. Place bracelet on wrist and go to a clear window, or go out into the sunlight. Watch the beads change color. Get out of the sunlight and watch the beads change back to white. Allow participants to test this as many times as needed to get their minds thinking. Discuss that the beads change color in the presence of sunlight, but turn white when shielded from it. Participants will want to test their beads against other light sources. Have other sources such as flashlights, overhead projector light, regular fluorescent light etc. available for them to test.
Assessment: Have the participants discuss and come to the conclusion that sunlight and not these other light sources affect these beads.
Exploration
Introduce a fluorescent black light to the participants. Discuss how this special light works. (http://science.howstuffworks.com/black-light1.htm) Demonstrate it on their clothing, shoes, teeth, and then their bracelets. Participants will see that the fluorescent black light affects their bracelets. They should come to the conclusion that their beads detect UV light.
Inform participants how the beads work, or have them find out on their own at: www.teachersource.com (Educational Innovations, Inc.)
Once participants conclude that the beads detect harmful, UV radiation, have them create an experiment in chart/graph form that shows objects to test for possible shielding of UV radiation using the tinted or clear cellophane, sunglasses, lotion sunscreens of various strengths, tinted plastic containers or glass jars from the materials section. Any other source that participants believe may be used as a shield or sunscreen may be added here as well. (scarves, T-shirts, umbrellas, etc.) Have participants state any conclusions found from testing these materials at the bottom of the graph/chart page.
Assessment: Check participants' charts for accuracy in testing and read conclusions that the students make concerning sunscreens.
Explanation
Lead the groups in a discussion of how they are aware of harmful UV radiation and how it can affect humans, animals, plants and manmade things. (sunlight fades/bleaches cloth and wood etc.) Then discuss that after people found that UV radiation harmed things they worked to create shields of UV rays in the forms of tints, colors, etc. (tinted glass bottles to store foods, medicines, etc.)
Assessment: Have participants go to the website: http://epa.gov/sunwise/kids/challenge.html This site challenges them at three levels (easy, medium, and hard) to see if they are "Sun Wise Kids". The activity explains answers and helps students to self-assess how well they are doing at surviving.
Elaboration
Participants can be introduced to another UV detecting source - UV detecting nail polish. Have them see how this works.
Assessment: Ask the participants to decide which detecting source is better, the beads or the polish? Tell how and why they have come to that conclusion in a persuasive paragraph. Share with partners and have peers evaluate. (A possible interdisciplinary/integrated work with language arts teachers.) "Invisible" writing pens and UV detecting clothing are also available.
Have the participants discover ways to use these sources along with or instead of UV detecting beads.
As a result of the professional opportunity in-service, the participants will become familiar with using UV light beads and various shielding devices to conduct an investigation of their own design and state a conclusion of their findings. Participants will then use this strategy to design a lesson for use in their classroom.
Content, Technology, and Professional Development:
NSES Content Standard B: Physical Science:
NSES PROFESSIONAL DEVELOPMENT STANDARD A:
NSES PROFESSIONAL DEVELOPMENT STANDARD B:
30-45 minutes.
Make certain to have enough beads and pipe cleaners/yarn for each participant to make a UV bead bracelet. Darkening the room by pulling blinds or turning off overhead lights makes the effect of the fluorescent black light better. Dividing the participants into partners or groups of three and giving each group one type of UV shield to test would work best. For example, give one group all of the bottles of sunscreen to test, then another group all of the tinted glass to test, and another group all of the sunglasses to test, and so on.
Pipe cleaner ends could poke or scratch skin.
Do not stare directly at the sun or any UV light source.
Take care not to shine a light source directly into anyone's eyes.
Some lotion sunscreens have PABA, which can slightly sting when applied to sensitive skin. Wear gloves to handle lotion sunscreens.
Take care not to break glass objects.
The sun loses energy by emitting light. A tiny fraction of that light reaches the earth, transferring energy from the sun to the earth. The sun's energy arrives as light with a range of wavelengths, consisting of visible light, infrared, and ultraviolet radiation.
Light interacts with matter by transmission (including refraction) absorption, or scattering (Including reflection). To see an object, light from that object-emitted by or scattered from it-must enter the eye.
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The facilitator may also wish to do a lesson on the study of human skin before using the UV beads. Participants will understand the need for protecting this vital body "organ" once they learn more about how important it is. An excellent lesson for this is found in Science and Children, Nov./Dec.1999, Volume 37, Number 3. Participants learn about skin using the learning cycle structure in this article. It addresses NSES Grades 5-8 Content Standard C and Content Standard A Science as Inquiry.
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Consider the following: have electrical outlets and/or extension cords available to easily allow all participants to access light sources and the fluorescent black light.
Allow for grouping with diversity in mind.
Encourage all participants to share in the discussion.
None available for this module.
