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Did you learn to swim by jumping in and doing it? Or did you take lessons and practice? I am a jump-in-and-do-it type person, whereas the enrichment specialist at my school is a take-lessons-and-practice type person. So when a new approach to teaching comes along, I enjoy working with her because she balances my splashes. This year we collaborated on an ecology unit with sixth graders that incorporated concept-based instruction into a problem-based activity. Students used their scientific skills of observing and inferring to explore and address an aerator problem in a pond ecosystem.
Developing a Concept-Based Unit
A major part of developing concept-based instruction is the use of an overarching idea to provide a conceptual lens through which students view the content of a particular subject. By using a conceptual lens to focus learning, students think at a much deeper level about the content and its facts (Erickson 2007). Using a conceptual lens also frames the learning in such a way that students are being asked to think and use language as a practitioner would in that discipline (Tomlinson et al. 2002). We used several steps in the process of developing our concept-based unit:
* Choose a topic of study. We chose to develop a concept-based unit around the topic of ecology with potential expansion into other units and topics taught at the sixth-grade level in science.
* Decide on a concept. We next decided on the conceptual lens of "change." In looking over the various lists on macroconcepts that can be found in the literature, we felt that change fit best (Erickson 2007). We then used a planning web to gauge how change would fit into other science units for possible future concept unit development (Figure 1).
* Develop essential understandings and questions for the unit. The next step in our unit planning was the creation of essential understandings based on New York Science Standards, National Science Education Standards, and our district's standards-based curriculum. These essential understandings provided the focus for student learning in a unit of study while the essential questions acted as a means to lead students to uncover these understandings (Figure 2).
* Develop a problem-based learning activity as the focus of the unit. The problem-based activity served as the framework for the conceptual focus on change and its relationship to ecology as well as fostering scientific thinking. The problem dealt with a change that had occurred with the pond located on the school campus--a pond aeration system had been added. The question we posed was, "Is this a good thing for the pond ecosystem?" This set the stage for students to use their scientific thinking to investigate the problem, ask questions, and find answers. The end product was the writing of a letter of recommendation to the District Pond Committee from the point of view of an ecologist using scientific evidence to support their recommendation on the pond aeration issue.
* Use inquiry-based investigations to explore the pond environment. The students used the same type of procedures and kits that scientists would use in the field. We used the procedures developed by the GLOBE program (see Internet Resources). By taking the time to thoroughly plan our unit, we felt ready to tackle concept-based learning.
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Figure 2.Understandings and essential questions.Understandings:* Organisms adapt to a changing environmentin order to survive.* Plants and animals are interdependent uponeach other and their environment.* A change in any of the components in anecosystem results in other componentschanging.* The Sun is the main source of energy forecosystems and organisms.* Matter undergoes changes in the formof cycles as it is transformed through theenvironment.* Photosynthesis is the process by which solarenergy is changed into food energy.Essential questions:Overarching:* Are there consequences if change doesn't happen?Topical:* Why do scientists call it an ecosystem?* Is it necessary that living and nonliving thingsinteract in an ecosystem?* Is change important in an ecosystem?* How do different factors affect an ecosystem?* Is it possible to progress as a nation and notchange our environment?* How do human activities affect Earth's resources?* Is it important that matter changes as a cyclein ecosystems? Why? Why are natural cyclesimportant to ecosystems?* How does energy change as it flows through anecosystem?
Introducing the Concept of Change
To introduce the concept of change to our students, we had them form small groups and brainstorm 30 examples of the concept of change. Students came up with ideas such as leaves changing colors, time, seasons changing, and change you receive from making a purchase. Next, the students needed to brainstorm 30 nonexamples. They then created four categories and sorted the examples into one of each of the categories. All of the examples had to fit a category and students soon realized that some examples could fit into more than one. This then required either modifications or consolidations of categories. Students came up with such categories as physical change, economy, outdoors, history, and humans. We then explained the idea of a generalization and asked the students to develop three to five generalizations using the information they had created, analyzed, and evaluated to form categories. The students in each group had many thoughts and ideas. They struggled with forming generalizations. It was a process that lent itself well to deep thinking. Some examples of student-generated generalizations were (1) everything grows at a different pace; (2) time is constantly changing so that affects things; and (3) change may be caused by people or nature. Student generalizations were placed on a word wall that was made up of the word change and our teacher-selected generalizations. These generalizations were (a) change leads to more change; (b) change can have positive or negative consequences; (c) change is inevitable; and (d) change may happen naturally or may be caused by people. We chose these four generalizations as they aligned best with the unit's essential understandings. Student generalizations were then grouped under one of the related generalizations. For example, the student generalization, "Everything changes in nature" would be placed under the generalization, "Change is inevitable." The word wall became a teaching tool and was referred to whenever we made connections back to the four generalizations throughout the teaching of the unit.
The Ecology Unit
Problem-Based Learning
Once the introduction of concept of change and its generalizations were completed, students were ready to begin the ecology unit. To help frame the learning and to promote scientific thinking, a problem-based learning activity based on a real problem was introduced to the students. The problem was designed to bring in all of the topics and skills that were embedded in the ecology unit. Students were prompted to think scientifically through the use of a modified KWL.
Purposeful questioning techniques were used to guide students to come to the conclusion that one of their main questions was, "What is an ecosystem?" Students tended to focus on the minor points such as "What is an aerator?" or "How does an aerator work?" Although these questions are important, they are not the overarching question. To help students uncover this question, prompts such as the following were used: "What do you know or need to know about the pond to find out whether the aerator is a good thing? What can you tell me about the organisms found in the pond? How do organisms rely on their habitat for survival?" The point of this line of questioning was to encourage students to start thinking about the interdependence that exists between organisms and the abiotic and biotic factors found in an ecosystem.
Once students understood the overarching question, "What is an ecosystem?" became the basis for introducing the key topics and ideas related to ecology. Periodically during the course of the unit, we revisited our pond aerator problem to see what additional questions the students still had.
Five Stations
As part of the investigation into the pond ecosystem, we used the hydrology protocols from GLOBE to create five stations (Figure 3). Students were assigned to a station based on their readiness level to handle the complexity of the testing protocol. Students were responsible for learning the protocols of their station only. This allowed them to become experts in that station and to share that information later with others. The necessary materials for each station were placed in 10 gal. plastic buckets to make it easy for the students to transport the materials to the pond. Also included in each bucket was a laminated copy of the GLOBE protocol for that station, water-sampling kit procedures, and data collection sheets. Materials can be obtained from any science supply company and some are at local drug stores. They do not need to be the materials that are specifically used by the GLOBE program.
It was important to follow school outdoor safety procedures during the water sample collection and testing. We made sure both were conducted under the direct supervision of an adult that was assigned to that station: the classroom teacher, the enrichment specialist, or a student observer from a local university. Children were reminded of the importance of keeping in eye contact with an adult when near the water. We practiced and used a buddy system, as well as practiced using a whistle (provided to each child) to use only in an emergency situation. A ring buoy with throw line was located at the pond. A cell phone with preprogrammed principal and school nurse numbers was also carried by the teachers. A first-aid kit was also on site. Other necessary safety requirements included disposable gloves, safety goggles, a waste bucket, and a reminder to children to dress appropriately for the outdoor weather, including enclosed footwear. To make the most of our experience at the pond, we had each group collect its bucket of materials, read the procedures, and practice in a dry run. This allowed us to monitor students' use of the materials and to ask and answer questions about the testing materials, procedures, and potential results. Students were required to bring in permission slips. Under adult supervision, students made pond observations, collected water samples, conducted testing, and recorded their results. This was accomplished in 50 minutes.
Sharing Data
The next class period was devoted to sharing the different stations' data with the whole group. Students were to look at the significance of the collected data and what it meant for the health of the pond ecosystem. Students were given a teacher-developed resource that summarized the particular component their station was measuring. The resource included a definition of the component, its significance to the pond ecosystem, and the range of normal testing values (see Print and Internet Resources). Part of the students' research focused on discovering the acceptable limits for the different sets of data collected. For example, students discovered that dissolved oxygen levels more that 4 mg/L were sufficient to support most aquatic organisms.
The collected data was compared to data that had been gathered over the years by various elementary groups as part of their fifth-grade pond unit. The students used this to look at changes that have occurred over time to the pond and to develop a baseline picture of the pond ecosystem. The students were then able to use their data and observations to investigate changes that may have occurred to the pond as a result of the new addition of a pond aerator system. This is much like the work ecologists do when they conduct environmental impact studies.
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Results and Assessment
Students were excited to write letters to the pond committee about the aerator. Studying and investigating a real-life problem that existed in their own backyard allowed students a rare opportunity to share their knowledge on a problem that they had become passionate about. We were pleasantly surprised by the students' use of content vocabulary and their application of science skills and processes in their letters (for a sample letter and a rubric, see NSTA Connection), for example:
* "The aeration system breaks down the algae that some organisms need to survive."
* "It clears duckweed into different parts of the pond, and it even puts more oxygen in the pond for fish and aquatic life. The aerator makes the pond healthier."
* "We found that there is 12 mg per liter dissolved oxygen. In addition we found more organisms have come to live in the pond."
* "The pond is healthier now for producers, consumers, and decomposers."
The concept of change was reinforced and reflected on throughout the unit. Students were consistently asked to reflect on what changes were taking place, categorize the changes, and place the changes into the context of the unit concept web. The idea that scientists use quantitative and qualitative data as a basis for their decisions throughout the process of an investigation was likewise an important part of the unit. In addition, formative and summative assessments were used throughout the unit to maintain focus on the content of ecology and the process of being a scientist and to document student mastery of identified learning objectives. Figure 4 is a warm-up in which students were asked to compare and contrast a food web with a food chain. This ongoing assessment was created to check student understanding on three concepts: food web, energy pyramid, and the connection between the two. Figure 5 shows the large group debriefing of this warm-up. By using this assessment, we were able to identify students who had a sound understanding of this concept, those who understood bits and pieces, and those who were still confused and had misconceptions. We were then able to use this information to adjust our instruction for the next class.
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Reflection
As teachers, this was our first attempt at building and using a concept-based learning unit to teach scientific learning. Our personal reflection is that we learned as much as our students, maybe even more. There are parts of the unit that we would definitely keep and parts that we would do a little differently. This is change at its finest! The ability to bounce ideas off of another person, ask questions, and reflect with someone cannot be underestimated. Throughout the unit both of us continued using our own approach to lesson planning and science. My desire to jump in and do the science often needed to be counteracted with the enrichment specialist's desire to step back and think out the steps. At times this made it easier for the students to know what had to be done and to do it safely. Alternatively, students were able to gain enthusiasm for the practice of science by my show of passion for the science. By combining our two different teaching styles, our students benefited. We both feel that our first attempt at planning a concept-based unit was a success.
References
Erickson, L. 2007. Concept-based curriculum and instruction for the thinking classroom. Thousand Oaks, CA: Corwin Press.
Tomlinson, C., S. Kaplan, J. Renzulli, J. Purcell, J. Leppien, and D. Burns. 2002. The curriculum of parallel practice. In The parallel curriculum: A design to develop high potential and challenge high-ability learners, 163-207. Thousand Oaks, CA: Corwin Press.
Print Resources
Avery, L., and C. Little. 2003. Chapter 5: Concept development and learning. In Content-Based Curriculum for High-Ability Learners, ed. J. VanTassel and C. Little, 101-124. Washington, DC: The National Association for Gifted Children.
Erickson, L. 2002. Concept-based curriculum and instructions: Teaching beyond the facts. Thousand Oaks, CA: Corwin Press.
Internet Resources
Pond and Lake Management www.otterbine.com/assets/base/resources/ PondAndLakeManual.pdf
The GLOBE Program www.globe.gov
What is Problem-Based Learning? www. udel.edu/pbl/cte/jan95-what.html
Connecting to the Standards
This article relates to the following National Science Education Standards (NRC 1996):
Content Standards
Grades 5-8
Standard A: Science as Inquiry
* Understanding about scientific inquiry
Standard C: Life Science
* Populations and ecosystems
Teaching Standards
Standard B:
Teachers of science guide and facilitate learning
National Research Council (NRC). 1996. National science education standards. Washington, DC: National Academies Press.
Bethany Schill (bschill@spencerportschools.org) is a sixth-grade teacher, and Linda Howell is an enrichment specialist, both are at Cosgrove Middle School in Spencerport, New York.
Figure 3.The five stations.Station What You NeedAlkalinity Alkalinity test kit [we used LaMotte]Testing Distilled water Timer Data sheet Map of pond GLOBE protocol and kit instruction sheet Clipboard PencilsNitrogen Nitrogen test kit [we used Hach model NI-14]Testing Distilled water Data sheet Map of pond GLOBE protocol and kit instruction sheet Clipboard PencilsDissolved Water test kit [we used LaMotte]Oxygen Testing Timer Distilled water Data sheet Map of pond GLOBE protocol and kit instruction sheet Clipboard PencilsWater Secchi discsCharacteristics GPS Camera Measuring tape Bucket with string to collect water Long-handle net Sampling pansWater pH meter and calibration solutionsTemperature Thermometerand pH Map of pond Data sheet GLOBE protocol and kit instruction sheet Clipboard PencilsStation What To DoAlkalinity This station tests for the ability of a bodyTesting of water to maintain its neutrality. This is especially important to those areas exposed to acid rain.Nitrogen This station tests for the amount of nitrogenTesting found in water. Too high levels of nitrogen can result in algae bloom.Dissolved This station tests for the amount of dissolvedOxygen Testing oxygen in water. This is an important indicator of a healthy water ecosystem.Water This station looks at the physicalCharacteristics characteristics of the pond site--turbidity, type of pond bed, location of pond, weather at that time, types of plants and animals found, population count, etc.Water This station tests different locations of theTemperature pond for temperature and pH level of theand pH water.
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