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Learning cycle stations at an after-school "tradeshow'' bring life science to life.

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ith the number of popular medical and forensics programs on television and many references in the media today, even elementary students can comfortably throw around terms such as cells, DNAy and artificial products. Though these young "CSI and the like" fans sound good, in reality, students' questions on these topics often go unanswered, or they are left with misinformation regardmg these concepts. So we—university science educators and the resource coordinator for an elementary school gifted program—teamed up to create accurate, developmentally appropriate, and exciting experiences with these topics for students in grades K-5. The result of our collaboration was an after-school science "tradeshow," which we appropriately named CLSI: Cool Life Science Investigations (CLSI), where more than 100 K-5 students came together to experience an afternoon of fun, learning, and the real-life drama of accurate science. Students took home the idea that the science presented in television dramas and in the media may not always be complete or accurate. Providing opportunities to explore accurate science concepts shown in media programs through programs such as this one can help students become savvy consumers of media science information.

A Model Format Events like CLSI are the result of a longstanding partnership between university science educators and the local public school district that includes field work for preservice teachers and professional development programs for inservice teachers. Planning for CLSI began at the end of the school year for the event to be held the following April. We began the planning process early to allow adequate time for applying for a grant from the local public school foundation during the fall semester. 26 Science and Children

That way, we would have funds available in January to purchase equipment and work with it in developing curriculum before the April event, We chose the tradeshow format because we thought a "booth"-style setup (essentially a learning center) was a logical and engaging way to provide students with an array of activities in an organized way. Choosing Activities Our next task was to choose specific activities for each topic that were grade-level appropriate, resulting in three stations each for grade K-2 and grade 3-5 students. Topic selection was guided by questions posed by students during ongoing science enrichment classes for gifted students at the school. We then developed our own learning-cycle lessons to address those questions. For gi-ades K-2, we planned three stations "CO(JI (Sharp) Teeth," "Cool X-Ray Vision," and "Cool Cells I." The intent of the stations was to develop observational abilities and to examine, compare, and classify animal jaws, animal x-ray images, and plant cells (viewed using microscopes) according to structural similarities and differences. For grades 3-5. we planned "Cool Cells II," "Cool Biochemistry," and "Cool DNA," which focused on developing accurate understandings of the structure of simple cells, the classification of substances as "natural" or "artificial," and the presence of DNA in nonhuman organisms. Stations accommodated groups of 10 students at a time, with each station featuring an investigation lasting 30 45 minutes. A curriculum guide was written to accompany each station. Each curriculum guide averaged about 10 pages in length, and all followed the same format. They began with a one-page "inventory" listing equipment


and consumable supplies needed for the activity. At a glance, volunteers could examine the accompanying kits and verify that they had everything required for their station. A single page of instructions provided detailed information on station setup prior to student arrival and station dismantling at the end of the event. Next, a learning cycle guide led the volunteer through a five-phase engage, explore, explain (or develop the concept), expand {or apply the concept), and evaluate learning cycle. Given the informal environment of the after-school tradeshow, the evaluate phase was accomplished as part of the expand phase. Because some of the volunteers had little or no experience with teaching inquiry science, we included scripted questions with answers. In the explain phase, we explicitly stated that students were not to be told the concept. Rather, the volunteers were instructed to use the script of scaffolding questions with answers to lead the students to articulate the concept for themselves. The materials to equip the six life science stations (Figure 1) were purchased through a $350 grant from the local public school foundation that was obtained by the gifted program coordinator. Recruiting Volunteers Volunteers and guest presenters were recruited during February and March and included parents (most with college degrees and some with chemistry or nursing backgrounds), engineering students from a local university, experienced teachers from the school, and a preservice teacher. The gifted program coordinator recruited teachers from the school faculty at faculty meetings and with a flyer/sign-up sheet. She recruited parents from lists of those willing to help with science enrichment activities gathered at PTA meetings, science fairs, and other parent events. An effort was made to recruit preservice teachers from elementary science education methods classes at the local university, but unfortunately other fieldwork conflicted with this afterschool event for many. We gave presenters the curriculum for their stations approximately two weeks before the event, so they could get comfortable with the material. Because this was the first experience with inquiry science teaching for many of the volunteers, explicit instructions for facilitating inquiry were provided in the curriculum guides. We also provided training "one-on-one" as requested by individual volunteers and were available during setup and throughout the event to answer questions and resolve tiny problems with equipment or materials.

Finally, after months of preparation, the big day arrived. More than 100 students along with parents or other

Figure 1. CLSI equipment and nnaterials. Item

Cost (to nearest dollar)

DNA Model

$50

Animal Bites

$73

(animal jaw replicas) Human X-ray Print Set

$26

Animal X-rays

$16

Biotechnology Kit

$111

pH Paper (5 packs)

$13

Litmus Paper (3 packs)

$10

Miscellaneous

$47

Poster Board (6)

$6

Prepared Plant Microscope Slides

Already at the school Already at the school

Prepared Animal Microscope Slides

adult caregivers, attended the QO-minute, after-school program to participate in the activities below. The event was free and all students enrolled in the school were invited to attend. Flyers were sent home and advertisements were posted at school entrances to encourage all students to participate. Cool Cells I The microscopes at the "Cool Cells I" station immediately caught the eyes of the K-2 students. Here, students first examined cross-sections of plant stems and other materials with the unaided eye and then with a magnifying glass. They connpared the amount of detail they could observe about plant structure. From this comparison, they developed the concept that scientists use instruments, such as the simple magnifying glass, to gain information that would go undetected by their unaided senses. Next, they applied this concept when they used a more complicated instrument, a microscope, to examine the plant materials studied earlier and obtain more detailed data. Cool X-Ray Vision

Students closely examined dental and hand x-ray images from children of different ages and observed how dental and hand structure changed with age. Students realized that the structural differences apparent in the xray images could be used to classify the images accordDecember 2007 27


ing to the age of the patient. They applied this concept when they viewed x-ray images of different species of animals, mcludmgfish, amphibians, reptiles, birds, and mammals. They observed differences in the skeletal structures of the animals and used those differences to classify the images according to animal species. Cool (Sharp) Teeth Cat and mmk skulls; animal tooth and jaw fragments; and color photographs of animals at the "Cool (Sharp) Teeth" station were on display for students to handle and compare. At this station, they investigated how a flat, dull tool like a mortar and pestle is well-suited for grinding plant leaves and seeds, while sharp, pointy tools like knives or scissors are well-suited for cutting or tearing "tough" materials like meat (simulated by pieces of moistened cellulose sponge). We invited students to feel the texture of leaves and seeds and small pieces of a moistened cellulose sponge. We explained that the pieces of moist sponge were intended to approximate the texture of meat, as it would be unsafe for the children to handle raw meat. We then showed the children a mortar and pestle and scissors and invited them to use these tools to break up the leaves and seeds and sponge pieces into smaller pieces. When each student had used both tools to break up each of the materials, we asked which tool was more effective at breaking up the leaves and seeds into smaller pieces. Students agreed that the mortar and pestle had been more effective to grind up the leaves and seeds into smaller pieces. Then we asked which tool worked better to break up the moist sponge pieces. Students agreed that the scissors were more effective at tearing up the moist sponge pieces. We connected the grmdmg and tearing activity with what happens in an animal's mouth when it chews food. Students then examined the animal teeth and jaw fragments to identify structures that resembled flat, dull grinding surfaces and sharp, pointy tearing surfaces to determine what type or types of food the teeth or jaw could chew best, They then classified each tooth or jaw fragment as belonging to a carnivore (meat eater), herbivore (plant eater), or omnivore (plant and meat eater) based on the diet for which it was best adapted. Finally, students applied the concept m a game where they matched up animal photographs with the corresponding dental fragments.

For Grade Cool Biochemistry At this station, grade 3-5 students characterized common substances that they knew from everyday experience to be "natural" products, i.e., coming from plants or animals as opposed to "artificial" products that are entirely human-made. These common substances 28 Science and Children

included apple juice, lemon juice, and vinegar as well as their own saliva. Students then characterized these common substances accordingto a "chemical" property, pH, to classify the substances as acids or bases. Students wear chemical splash goggles and gloves when conducting these experiments. The pH projicity was selected because it can be easily studied by elementary school students using colorimetric indicators like litmus and pH paper. Their results showed that the juices and vinegar were acids, and thai saliva was neutral or slightly acidic. From these data, they developed the concept that living organisms produce substances thai can be identified by a chemical property and, hence, artm fact "naturally" made chemicals. Cool DNA Students were drawn to the "Cool DNA" station by a colorful three-dimensional model of the DNA double helix displayed alongside images of the double helix. Volunteers queried participants on what they already knew about "DNA." Most responses from students and from some parents associated DNA with forensic analysis-—how DNA is usually mentioned in the popular media. Volunteers asked students to consider whether DNA was only found in humans. Rather than provide an answer, they invited students to explore whether DNA could be obtained from a fruit, specifically a strawberry. Students were given a resealable plastic bag. Each bag contained a thawed, previously frozen strawberry along with a liquid dishwashing detergent for hand washing dishes (not automatic dishwasher detergent) and salt solution. Students squeezed ihibag to mash the strawberry and thoroughly mix it witli the solution. This mixture was poured through a iiltt'r into a test tube. Students poured chilled ethanol down the side of the test tube. Wear chemical splash goggles when working with any liquid. They observed the solution separate into layers ineluding a layer of a white, milky, mucouslike substance that could be "spooled" around a glass rod. Students were asked to observe the physical properties of the substance and compare this to known physical properties of DNA, described as a material characterized by a whitish, milky color, and mucouslike texture that can be spooled around a glass rod, like thread. On the basis of the similarity between the properties of the substance that they had obtained from the strawberries and the known properties of DNA, they concluded that the materia! they had obtained from the strawberries was DNA. Children and even some parents expressed surprise at obtaining DNA from a strawberry. Comments like "we didn't realize that there was DNA in plants," confirmed that they grasped the concept that humans are not the only organism that has DNA.


CLSI: Cool Life Science Investigotions

Cool Cells II At this station, students used a microscope to view detailed patterns in onion skin and other plant materials, They also studied the onion or plant cells that they couldn't see with the unaided eye or even with a magnifying glass. From these observations, students developed the concept that scientists use instruments to obtain data that is inaccessible to their unaided senses. Students applied the concept as they divided mto three groups with each group viewmg a different microscope slide: a) spirogyra; b) pollen; and c) cotton fiber. The students reconvened and, like scientists at a scientific conference, reported on the particular slide that they had studied under the microscope.

Durmg the 90-minute CLSI event, the children's enthusiasm to work on the experimental investigations and expressions of "Wow!" and "That's cool!" as they came to understand a new concept provided immediate feedback that the event was a success. Parents' and teachers' accolades after the event confirmed the positive impressions that we formed as we watched the students intently huddled around the volunteers at the stations. Volunteers indicated that they had newly learned or reviewed some of the science content and recognized the difference between how they had been taught science (presumably by direct instruction) and the int]uiry science learning that they had participated in during the event. Parents who attended as guests had an opportunity to experience inquiry science learning and came to appreciate the type of science learning activities that their children regularly have in classes in this public school district. We considered the event an "advertisement" for the new science equipment and materials that the gifted program coordinator had obtained for overall school enrichment. After seeing it demonstrated, we hoped that teachers would be more likely to incorporate these materials in their own classroom science instruction. Based on our observations of the stations as well as in response to volunteer suggestions, we plan to make some modifications to future events, such as Incorporating new activities into the curriculum for each station to keep the content "fresh" and give students different life science learning experiences. We are considering scheduling future events in the evening, perhaps on the name night as a regularly scheduled PTA meeting, as this might add to our volunteer pool and make the event accessible to preservice teachers. We also brought CLSI to the classroom by encouraging preservice teachers doing fieldwork at the school to adapt the CLSI curriculunn for formal classroom lessons. This was another way to make

Connecting to the Stondords This article relates ta the fallowing National Science Education Standards (NRC 1996): Science Teaching Standards Standard D: Teachers of science design and manage learning enviranments that provide students with the time, space, and resources needed for learning science. Standard E: Teachers of science develop communities af science learners that reflect the intellectual rigor of scientific inquiry and the attitudes and social values conducive ta science learning.

teachers at the school become aware of the equipment and materials available to them for their own classroom science teaching. When we designed the CLSI after-school event, our intention was to improve our students' life science content knowledge about topics that are regularly touted on television and other mass media encountered by the students. Our hope is that by countering the sometimes exaggerated or inaccurate science presented in the popular media with accurate, developmentally appropriate direct science learning experiences, we can promote students' critical evaluation of information presented by the media. As we saw children change their minds about what substances were "natural" and what were "artificial" and recognize that DNA was not only found in human beings, we felt that we had taken a step toward realizing this goal. • Florence F. McCann (finecann@sbcglobal.nct) is a doctoral student in science education at the t/nji'ersit;y oj Oklahoma in Norman, Oklahoma. Edmund A, Marek is Presidential Professor and Center Director of the Science Education Center, and fon E. Pedersen is Associate Dean for Research and Graduate Studies, College of Education, and Center Co-Director of the Science Education Center, also at the University of Oklahoma. Carell Ealsarella is a gifted resource coordinator who teaches classes and develops schoolwide enrichment programs at Washington Elementary School in Norman, Oklahoma. They would like to thank Washington Elementary Schooi principal Linda Parsonsfor her support ofscience enrichment activities at the school.

National Research Council (NRC). 1Q96. National science education standards. Washington, DC: National Academy Press. December 2007 29



Cool Life Science