Article pubs.acs.org/jchemeduc
Biodiesel and Integrated STEM: Vertical Alignment of High School Biology/Biochemistry and Chemistry Andrea C. Burrows,*,† Jonathan M. Breiner,‡ Jennifer Keiner,§ and Chris Behm∥ †
Secondary Education, University of Wyoming, Laramie, Wyoming 82071, United States Education and Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States § Athletics, University of South Carolina Upstate, Spartanburg, South Carolina 29303, United States ∥ Science Department, Troy High School, Troy, Ohio 45373, United States ‡
ABSTRACT: This article explores the vertical alignment of two high school classes, biology and chemistry, around the core concept of biodiesel fuel production. High school teachers and university faculty members investigated biodiesel as it relates to societal impact through a National Science Foundation Research Experience for Teachers. Using an action research approach, two high school teachers created and implemented biodiesel lessons in both biology (biochemistry algae focus) and chemistry (transesterification focus). This article describes the extent to which this integrated STEM biodiesel lesson, which is vertically aligned in one high school, affected the students’ skills and attitudes in relation to STEM subjects. The lesson plans used and the student outcomes based on the biodiesel activities are provided on the basis of a year’s implementation. Overall, student skill sets and attitudes improved based on pre−posttest data and classroom indicators, such as student questions. One implication of this work includes a stronger integrated STEM vertical curriculum that could be implemented in any biology and chemistry program, especially in advanced placement (AP) classes such as AP chemistry, to encourage and engage students in discovery, inquiry-based learning, problem-based learning, engineering design, and creating experiments that have a real-world applicability such as those with socio-scientific issues. The notion that science disciplines are an interconnected web of concepts is highlighted. This contribution is part of a special issue on teaching introductory chemistry in the context of the advanced placement chemistry course redesign. KEYWORDS: High School/Introductory Chemistry, Biochemistry, Collaborative/Cooperative Learning, Hands-On Learning/Manipulatives, Inquiry-Based/Discovery Learning, Problem Solving/Decision Making
You’re Glumping the pond where the Humming-Fish hummed! No more can they hum, for their gills are all gummed. So, I’m sending them off. Oh, their future is dreary. They’ll walk on their fins and get woefully weary in search of some water that isn’t so smeary.
alternative fuels, students can succeed through integrated science, technology, engineering, and mathematics (STEM) curricula. When teachers develop open-ended activities, and students create and explore research questions, that align biodiesel production with curriculum standards in the four different science courses (as well as other STEM classes), students can construct their own knowledge through meaningful learning. In this article, the authors introduce the vertical alignment of biodiesel using biology (with an algae focus) and chemistry (with a transesterification focus). These lessons allow for transformation of traditional pedagogies via the inclusion of integrated STEM, infused with critical thinking strategies in AP Chemistry (or other courses), through laboratory investigations.
The Lorax
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r. Seuss1 wrote the children’s book, The Lorax in 1971 at a time of extreme environmental concerns due to human impact. Today, global climate change is a topic that involves often highly controversial discussions. Most secondary students realize there are problems with climate change, pollution, and natural resource reduction, but they do not understand their magnitude and scope. Biodiesel engineering, or biodiesel fuel production, can be used as a topic of vertical alignment across the high school science curriculum to teach students differing concepts in physical science, biology, chemistry, and physics related to climate change, pollution, and sustainability topics. While building their content knowledge, learning via teacher scaffolding,2 and applying their new content knowledge of © XXXX American Chemical Society and Division of Chemical Education, Inc.
Special Issue: Advanced Placement (AP) Chemistry
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FRAMEWORK: MEANINGFUL VERSUS ROTE LEARNING Teaching involves encouraging students to use “meaningf ul learning by using tasks that actively engages the learner in searching for relationships between his/her existing knowledge and the new knowledge”.3 The nature of science (NOS) and science-technology-society (STS) pedagogies incorporated with experimental procedures in a classroom can supplement meaningful learning.4−7 Meaningful learning occurs when students build their knowledge based on prior knowledge/ discovery learning. The teacher’s role in meaningful learning is to guide students through their discoveries and provide new challenges to students once they have attained a certain level of knowledge. Rote learning is where students “make little to no effort to relate new information to relevant prior knowledge”.3 In rote learning students mainly memorize information. The teacher’s role in rote learning is minimal and few if any content connections are revealed to students. Explicit connections are vital to meaningful learning, and the authors use Vygotsky’s8 social constructivist theory as a framework to aid that student learning. Using a constructivist framework to address biodiesel production can result in meaningful student learning with rich connections, particularly if there is vertical alignment among STEM courses that are integrated.
the vertical alignment described in this article, the study displays that having several teachers from the same school, teaching about the same unit also has a positive impact on student learning. “The results underscore the importance of professional development and collegial support in enhancing student success in inquiry science”.21 Inquiry-based learning improves the quality of education with interactive, studentdirected methods with a focus on how to learn.22,23 Some argue that problem-based learning (PBL), where students are decision-making, exemplified by inquiry-based learning, should be the focus, or at least a major component of skilled learning.24 Capraro and Slough defined PBL as “well-defined outcome with an ill-defined task”.25 The tasks that students perform should be authentic opportunities to observe, acquire, apply, and consolidate ideas.26 Students are learning in a collaborative, cooperative environment. On the basis of this information, whether it is called inquiry, problem-based learning, or exploring socio-scientific issues, focusing on real-world applications while students are engaged in questioning and experimenting is essential for increased student learning.27
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RET EXPERIENCE AND RESEARCH QUESTION
The National Science Foundation (NSF) funded a Research Experience for Teachers (RET) summer program at the University of Cincinnati (UC) from 2006 through 2012. The RET program was designed to provide teachers with an authentic engineering research experience through STEM integration. After reflection and discussion with their colleagues regarding their authentic learning experience, teachers used their STEM integration research experience to design and implement lesson plans based on PBL, inquiry-based learning, engineering design, SSI, process skills, communication, and nature of science.28,29 Eight in-service teachers and four preservice teachers were chosen to work together in UC research facilities for 6 weeks on six different research projects that all focused on energy and environmental conservation. The teachers believed that they could work alongside their mentors (research engineers), and that they could transfer the experience to their students.28 In-service and preservice teachers enacted projects with PBL, inquiry-based learning, engineering design, and SSI decision-making during the following school year. One of the six RET projects was entitled: Making Biodiesel for Research and Education. A general biodiesel production overview is presented in Figure 1. For this biodiesel project, the overall goal was to determine a more sustainable and viable way to make biodiesel fuel. After this summer experience, the teachers (coauthors Keiner and Behm) asked if high school biology and chemistry students would have an increased STEM interest if they participated in a biodiesel project. Thus, the research question that guided the biodiesel integrated STEM lesson development and implementation was, “Does an integrated STEM vertically aligned lesson af fect high school students’ skills and attitudes in relation to STEM subjects?”
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LITERATURE REVIEW Fostering habits of “good thinking” in science will permit students to explain, demonstrate, suggest, and solve problems, furthermore “good thinking” involves the “learning is difficult” concept, expectations of ideas, and creation of a valued thinking environment.9 Oral questioning can be another powerful tool to use, and focus/reflection on questioning can improve inquiry and students’ higher order thinking.10 Accordingly, reflection on teacher and learner roles is an important component to support content learning.11 The views of science teachers, as well as the designs and implementation of their lessons, impact student learning12 and classroom activities should address this issue. Researchers agree that content (and context) knowledge needs to be translated into useful pedagogical knowledge (PCK) in order to teach students well.13 Teachers’ PCK improves when there are multiple opportunities for them to practice analysis.14 One area that produces interesting questions for inquirybased learning, and that encourages student knowledge acquisition, is socio-scientific issues15 (SSI). Biodiesel fuel production, as a SSI, is created by science and involves technology use, ethical dilemmas, and societal issues. Tytler16 reviewed SSI studies and found that promoting wider viewpoints by investigating competing positions and interests was vital for student learning. Interestingly, some SSI researchers have shown that connection to17 and attitude about a certain topic might be more important than the content knowledge itself.18 Debates and ethical dilemmas can aid in changing student attitudes and topic perception.19 Student exploration through inquiry is key. Inquiry-based learning can be defined in many ways, from structured to open, involving differing amounts of learner self-direction and amount of teacher/material direction.20 With this context in mind, inquirybased learning is important for students, and Liu, Lee, and Linn’s21 study show that teachers who value inquiry-teaching strategies have students who score higher on content tests and are able to integrate subjects more effectively. Additionally, like
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METHODS: FROM THE LAB TO THE CLASSROOM In this action research project, meaningful, integrated learning was the primary goal. Using research experience as a base, the authors developed biodiesel lessons (biochemistry lessons) that were aligned with state standards and could be taught through the high school science curriculum. Additionally, the recently released Next Generation Science Standards30 highlight the biodiesel lesson components with the importance of engineerB
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natural and synthetic energy resources. In 10th grade biology, students examined different sources of biodiesel and then took part in a study of how processes were improved by growing algae to understand properties of photosynthesis and eventually biodiesel production. In 11th grade chemistry, students discovered the reaction of biodiesel and made their own batch of biodiesel from waste cooking oil, while learning about concepts such as energy changes and stoichiometry. Finally, in 12th grade physics, students tested the efficiency of biodiesel and analyzed heat and energy transfer of biodiesel through a working engine. During the four vertically aligned lessons/ courses, students discovered different career opportunities related to their in class research experience, and students built their repertoire of real-world applications and societal impacts. Figure 2 illustrates the vertical alignment using biodiesel. This article explains the development and initial teaching of the biology and chemistry biodiesel portions especially concentrating on PBL, inquiry-based learning, engineering design, and SSI. Since most students encounter biology before chemistry, those lessons are presented first; however, the lessons could be adjusted to fit grade level offerings within any high school and the curriculum could be used to meet the needs of the new AP Chemistry’s Big Ideas and Science Practices for AP Chemistry.
Figure 1. Biodiesel production overview.
ing design, integrated STEM, and crosscutting concepts (e.g., Cause and Effect and Systems and System Models) that fit into disciplinary core ideas (e.g., Earth and Human Activity and Weather and Climate). The biodiesel lessons presented in this article provide “foundational ideas in science with activities and language that would build upon [prior knowledge] and develop cognitive structure that could facilitate the learning of all science in later years”.3 The program began in 9th grade physical science, where students were introduced to energy concepts via different fuel sources and examined the positive and negative effects of the uses and development of these
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BIOLOGY IMPLEMENTATION Since biology is the most popular college science field of study,31,32 a high school chemistry teacher can integrate biology for examples and topics to interest students in chemistry. The following biology lesson can be used as a chemistry-in-context
Figure 2. Vertical alignment using the integrated STEM concept of biodiesel. C
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Table 1. Biology Student Goals and Objectives in the Biodiesel Lesson
results found in those classrooms. The following algae lab incorporates the photosynthetic processes and links it to biodiesel production research through PBL, inquiry-based learning, engineering design, and SSI. Secondary students can then use their knowledge of photosynthesis to develop a further understanding of real-world engineering applications through biodiesel fuel production.
experiment in a chemistry classroom as well. Contextual information prepares the students for this biology/biochemistry topic. In 2010, America was using 19.18 million barrels of refined petroleum products and biofuels per day, and that was estimated to be 22% of the total world petroleum consumption.33 In 2011, total U.S. greenhouse gas emissions were 6702.3 Tg, or million metric tons CO2 equivalent. Total U.S. emissions increased by 8.4% from 1990 to 2011.34 With the increased demand of oil, need to import foreign oil, and amount of pollution emitted from the burning of oil, the United States has realized the many societal and economic problems associated with the continued dependence on oil. Global climate change is currently a hot topic. Many alternative energy sources have become of interest to help lower the dependence on oil. Biodiesel fuel has become of special interest because its use would not involve expensive changes to automobile engines and other machines. The burning of biodiesel also reduces the amount of particulate matter, CO2, and sulfur oxides emitted into the air, thus offering a cleaner burning alternative to oil. There are many renewable sources that can produce biodiesel fuel such as waste cooking oil, soybeans, corn, and algae. “Microalgae are sunlight-driven cell factories that convert carbon dioxide to potential biofuels, foods, feeds, and high value bioactives”.35 Algae can be a great renewable source of biodiesel as well as an important teaching tool in biology to highlight biochemistry components. Many curricula in biology include standards in cell structure, function, and respiration, and include photosynthesis processes. Students and teachers have created biodiesel from algal lipids in other classrooms36 and the biodiesel lesson presented here substantiated the
Lesson Overview
In the biology/biochemistry biodiesel cooperative learning lesson, the applications, career connections, and societal impacts were discussed and debated at length (Table 1). The standards addressed related to human activities, natural systems, flow of energy, cycling of matter, and ecological systems. Common misconceptions addressed included the following: (1) Energy only flows from the top of the food chain down (2) Organisms in a population are important only to their prey (3) Populations will increase indefinitely because resources are unlimited (4) The greenhouse effect is caused when gases in the atmosphere behave as a blanket and trap radiation, which is then re-radiated to the earth (5) Energy is lost in the system (6) Energy can be recycled through an ecosystem many times These biology/biochemistry misconceptions were found using the AAAS Science Assessment site37 and through teacher insight after teaching the subject. Materials for this lab included D
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algae samples, test tubes/holders, pipettes, light sources with colored light filters, light microscope, oxygen sensor, wet slides, and water. Assessment questions incorporated the following concepts: (1) Describe the process of photosynthesis (2) Explain the light conditions required for the most algae to be produced (3) Explain the temperature conditions required for the most algae to be produced (4) How does the color of light affect the algae growth (5) Explain what happens to the oxygen levels throughout the 5 days of algae growth and why is this important to note (6) Describe the applications, career connections, and societal impacts of biodiesel production (7) Argue for or against using algae to make biodiesel
Figure 3. Various algae strains that could be used in the biology/ biochemistry biodiesel lesson and provide (A) real-world contextual examples or (B) highlight unique characteristics of specific strains. (A) Synechoccus and Chloroflexus; image Courtesy of the Authors. (B) Fremyella diplosiphon; image courtesy of Indiana University. Copyright 2005 David Kehoe, Rick Alvey, and Roger Hangarter.
Photosynthetic Rate of Algae Under Varying Conditions
This lab can be completed before or after students have basic knowledge of the process of photosynthesis; however, when the lessons are finished the students can describe and explain that plants use photosynthesis to convert carbon dioxide, water, and light into energy (glucose sugar) while oxygen is given off as a byproduct. In this experiment, students worked with different forms of algae to discover what conditions the algae favor most, focusing on temperature and light intensity. In the classroom, students determined the conditions under which the algae had the highest photosynthetic rate. Students were introduced to the concept of biodiesel production as a source of alternative fuel, but the concept that plants produce a relatively small amount of oil was highlighted. The large biomass needed to produce the amount of oil desired, as well as the concept of sustainability, were used as a SSI platform for debate, and the teacher encouraged more debate surrounding concepts such as genetic engineering (e.g., Can a plant’s genetic makeup be altered to produce more oil? Should it? How?). Students conducted research and compared other plants as feedstock for biodiesel production. The growth of algae was tied to the concept of photosynthesis, an overarching concept in biology. Table 1 describes the goals and objectives for the students. To begin, the 56 biology students formed groups and wrote hypotheses to describe the algae that and the strain that would produce the most oxygen and/or oil. Students then prepared eight test tubes, two of each strain of algae (Figure 3). Small kits of the algae can be purchased from several Web sites.38 Students sampled the algae and solution into smaller test tubes for each strain. After the test tubes were prepared, students took an initial oxygen reading from each test tube using a dissolved oxygen sensor (e.g., PASCO) and created wet slides of the samples for microscope viewing. As a control, the students tested the dissolved oxygen level of the tap water. The test tubes were placed under different conditions including varying temperature and light sources. One visually appealing example was Fremyella. This algae changed color based on the light source, and placing test tubes under different colors of light allowed students to observe varying hues.39 Over the seven-day lab, students recorded and analyzed data specifically relating to the dissolved oxygen content. As a second lab portion, to extract the oil from the algae, students used an olive press (yielding about 75% of the oil), however, in the upcoming year’s chemistry class, students had the option of using an additional hexane solvent method to remove the algae oil
(yielding about 95% of the oil). Biology classroom daily procedures included the following: • Day 1: Review photosynthesis/algae; students prepare algae test tubes (light and temperature variables); students set up recording/observation log for dissolved oxygen • Days 2−5: Students take daily readings and record dissolved oxygen levels from each test tube; students suggest alternate set-ups; students debate pros and cons of algae-created biodiesel; students set up oil production methods for testing; students test algae oil production • Days 6−7: Students create analysis report and present findings During the 7 days of algae growth, students tested the dissolved oxygen, prepared wet slides of samples to view under the microscope, documented the data into the recording log sheet (including drawings), and debated sustainability of algae for biodiesel production. Students removed samples and looked under a light microscope to observe and record the different shapes and colors of the algae. By the end of the lab, students determined which conditions were optimal for growing algae and what type of algae produced the most oxygen. There were no special safety concerns in the algae lab; however, students followed regular lab safety guidelines. Lab Report
Growing algae is easy in a classroom setting (Figure 3), but making biodiesel from algae can be a somewhat complicated process. Barriers to making biodiesel can be the expense and the difficultly of obtaining the proper equipment and expertise. Making large quantities of biodiesel from algae is not feasible in a high school classroom setting (consider partnering with a university’s engineering program), but smaller batches are possible. Even if biodiesel is not produced, but the photosynthesis/algae experiment is completed, it is important for students to realize the implications of biodiesel as an energy resource and the process by which algae produces biodiesel. As part of the final lab reports, students explained how biodiesel is made from algae, and then used the photosynthesis lab results to recommend a set of parameters to grow algae that will result in the largest amount of biodiesel production (specifically referring to temperature and light parameters). Additionally, E
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Table 2. Chemistry Student Goals and Objectives in the Biodiesel Lesson
students were encouraged to develop further engineering connections (as diverse as the favorable impact on the environment relative to current fuels), consider the potential economic impacts in rural areas that are large enough to host ponds of algae farms, and analyze the cost benefit of the efficiency of different algae’s oil production versus currently utilized fuels.
(3) Explain the conditions that would allow algae to create the most oxygen (4) How are algae and biodiesel related? The pretest scores showed that 21% of the students scored greater than a 75% (12 of 56 students). The post-test scores showed 73% of the biology students scored greater than a 75% (41 of the 56 students). The biodiesel learning gains, based on the pre/post tests, were greater for concepts as measured by pre/post assessments throughout the year. On the basis of student feedback, Keiner believed that the students valued learning about biodiesel through an ecological viewpoint. Although the students were novices with respect to using the probeware, they thought that the activity was engaging and interesting to execute. Positive student feedback included, “It was very interesting to work with something new” and “I liked how it was hands-on and we had to actually think. Each lab group got a little bit dif ferent answers”. Student comments for improvement included, “Researching was boring” and “I didn't like not having a right answer”. Some students struggled with the connection of oxygen level readings and algae growth. Yet, when environmental awareness was introduced the following year in chemistry, overall the students used the prior information from the ecology unit to connect to the chemistry unit. Having an authentic STEM integrated biodiesel theme helped the students connect to and retrieve prior content knowledge. Additionally, having students debate issues and struggle with indefinite findings, allowed them to experience an open-ended inquiry lesson. In an end of the year review, Keiner stated, “It was nice to see that [the students] came to an idea of what engineering can be, since some of them have interests that are far away from any science, to suddenly see a connection and what is
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BIOLOGY FINDINGS AND REFLECTION At the end of the summer RET experience, Keiner stated, “I got a lot of ideas about implementation f rom my research project. I would naturally teach about algae in biology, however, I have not taught it in combination with alternative f uels. This project gave me another idea of how to implement real-life research in my teaching”. Keiner performed this lab during an ecology unit in the following fall semester. After students learned about natural resources, they began a renewable resource unit, and the lesson plan integrated perfectly requiring no restructuring of the curriculum. The students interacted during the lesson, debated different topics, used probes to take dissolved oxygen level readings (with temperature and light variables), and created wet slides to determine the structure of the algae. In the future, Keiner would suggest guiding the students’ work through a series of learning progressions, along with the specific content discussions, as a crucial factor in student learning. For the biology class, the vertical alignment with the biodiesel activity promoted meaningful learning based on pre/post test scores. The pre- and post-tests were identical and included four questions: (1) Draw the photosynthetic cycle (2) Describe optimal conditions for algae growth F
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happening around them... . It was good to see them in class, to see them happy and active... to see them envision themselves as an environmental engineer. I heard one pair of students debating if a bioengineer was better than an environmental engineer - that’s the kind of stuf f I want to hear!” In answering if an integrated STEM vertical lesson affected high school chemistry students’ skills and attitudes in relation to STEM subjects, Keiner agreed that there was an increase in positive attitudes, engagement, and skill set; yet there was room for improvement in future years.
Safety concerns involved burns that could be associated with sulfuric acid and sodium hydroxide, the flammability of methanol, and wearing proper safety gear. Prior knowledge required for this unit included balancing equations, titration experience, and stoichiometry. Students worked in engineering teams using WCO from the school’s cafeteria. They were given the method of titration to determine the free fatty acid (FFA) content of the sample and used this amount to determine how much NaOH and methanol reacted with the WCO to produce biodiesel. Scheme 1 shows the basic transesterification reaction used to create biodiesel from waste oil.
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CHEMISTRY IMPLEMENTATION Implementation of the cooperative learning biodiesel lesson into a chemistry classroom connected many different concepts through PBL including: inquiry-based learning, engineering design, and SSI based activities (e.g., balancing equations with candy and toothpick modeling). Shorter lessons, implemented in other chemistry classrooms, than the one presented here are available.40 Several state and national standards were addressed through biodiesel topics (e.g., chemical reactions, system models). Table 2 contains the goals and objectives for the chemistry biodiesel lesson. Specific important concepts of making biodiesel fuel included: (1) Biodiesel is composed of a long chain of carbon atoms with attached hydrogen atoms and an ending ester functional group (2) Diesel engines can burn biodiesel without modification (3) Vegetable oillike biodieselbelongs to the ester compounds (4) Removal of water is crucial in making biodiesel (5) Soap can be made if water is not removed correctlythis complicates the transesterication reaction.
Scheme 1. Basic Transesterification Reaction of Waste Cooking Oil into Biodiesel
Basic titration techniques were used for the four-day lesson. First, the 53 students made a 0.1% NaOH in water solution: 1 g of NaOH dissolved in 1 L of distilled water. They titrated the fatty acid using a phenolphthalein indicator. Each 1 mL of NaOH solution corresponded to 1 extra gram of NaOH they needed to add per liter of WCO when making the biodiesel, just to eliminate the FFAs in that WCO. If the WCO took more than 4 mL of NaOH solution, students did not use it. Average WCO requires approximately 3 mL on the titration, and poor quality WCO can take 10 mL or so, which is completely unusable with a NaOH catalyst. Students used the following equation to determine the NaOH required:
Lesson Overview
The applications, career connections, and societal impacts were discussed at length in the chemistry biodiesel hands-on learning lesson (Table 2). The standards addressed related to chemical reactions (e.g., endothermic/exothermic), issues of environmental quality (e.g., population growth, resource use, capacity of technology to solve problems), forces, motion, cause/effect, and systems/system models. Common misconceptions included: (1) Substances always react in a 1:1 ratio (2) Substances react by equal weight (3) A mole always contains 6.02 × 1023 atoms (4) Chemical reactions are a change to the initial substance and not a physical interaction between atoms These chemistry/biochemistry misconceptions were found using the AAAS Science Assessment site37 and through teacher insight after teaching the subject. Materials included waste cooking oil (WCO), methanol, sulfuric acid, sodium hydroxide, indicator solution, hot plates, pipettes, beakers, graduated cylinders, biodiesel reactor, and calorimeter. Assessment questions incorporated the following concepts: (1) Why are stoichiometry and balancing equations important to chemists and chemical engineers? (2) Why is stoichiometry important to biodiesel production? (3) What types of chemical reactions are used in biodiesel production? (4) What is transesterification and why is it important?
WCO (L) × (5 g + titration_amt)/L
For example, if the titration required 3 mL of NaOH solution, that translated to an extra 3 g of NaOH for each liter of WCO. If they used 50 mL (0.05L) of WCO, the amount of NaOH needed to make biodiesel with the WCO: 0.05 L(5 ́ g + 3 g)/L = 0.05 L × 8 g/L = 0.4 g
After the biodiesel was made, the samples were compared using a calorimeter to determine which produced the most abundant sample. Basic daily steps included the following: • Day 1: Demo/titrate 1 mL sample of WCO with NaOH to determine the FFA content; students used FFA% conversion equation to determine the amount of NaOH that should be added to a 500 mL reactor to convert the FFA to under 1% • Day 2: Students received 100 mL of WCO and used equations/methods to prepare biodiesel41 • Day 3: Students washed the biodiesel with water42 • Day 4: Students debate the best procedure for making biodiesel; students test biodiesel samples with calorimeter to see which group made the most efficient biodiesel Groups determined if there were any methods or data that helped them create a purer or an equivalent product using fewer raw materials.44−48 When the activity was complete the teacher explained that the students had just acted as a chemical engineers, an engineer that identifies and designs more efficient G
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be carried throughout the course possibly allowing for students to more readily make explicit connections between the learning objectives and general course content. The authors recommend that teachers consider using the biodiesel theme across all 6 Big Ideas in AP Chemistry as follows: • Big Idea 1 states that atoms and elements are the building blocks of matter. Teachers can use the transesterification reaction components when illustrating the following subtopics: atomic modeling, molecules and elements, symbolic representation, molecules and elements, chemical analysis, and the mole. • Big Idea 2 deals with chemical and physical properties of matter. Teachers can use the components of this biodiesel lab to illustrate intermolecular forces, Lewis and VSEPR models, solutions and bonding. • Big Idea 3 addresses chemical change. Teachers can use the biodiesel theme to teach molecular equations, stoichiometry, neutralization and displacement reactions, chemical change evidence, and endothermic and exothermic reactions. • Big Idea 4 focuses on chemical kinetics. Teachers can use the biodiesel theme to examine the concepts of rates of reaction and catalysts. • Big Idea 5 is based on thermodynamics, highlighting the role of energy when matter changes. The biodiesel concept has many avenues for revisiting under this big idea: temperature, heat and energy transfer, conservation of energy, calorimetry, bond energy, biological systems, and enthalpy of reactions. • Big Idea 6 deals with chemical equilibrium. The main areas where teachers can use the biodiesel theme are reversible reactions, acid−base equilibria, Le Chatlier’s principle, and solubility. For example, teachers could have students do the calorimetry calculations to determine the oil’s enthalpy of reaction, and have students compare it to enthalpy of reaction calculated using bond energies. Students can build models of the different molecules in the lab and discuss VSEPR arrangements for molecules with more than one central atom and the resulting intermolecular forces. How teachers introduce each subtopic within a big idea is up to them, but this theme allows for many cross connections among the Big Ideas and subtopics that introduce the enduring understandings and essential knowledge as indicated in the new curriculum. Additionally, the Science Practices for AP Chemistry fit into biodiesel production lessons (e.g., representations, mathematics use, questioning, data collection, data analysis, explanations, and content connections). Teachers will undoubtedly find that the biodiesel theme can extend into more concepts and science practices than indicated above.
methods of chemical production (e.g., design, test, analyze, brainstorm, redesign, retest, repeat). Students recognized that they produced a fuel capable of running a vehicle, and a diesel generator was brought in to show students that they produced a “real-life” fuel. This lab was an open-ended inquiry lab, following an iterative engineering design process, in which students debated product outcomes and created solutions to convert unusable WCO to useable biodiesel as well as convert unusable biodiesel to useable biodiesel. The biodiesel activity highlights the application of titrations where students can observe at least five chemistry concepts: 1. Identify combustions 2. Identify displacement and neutralization reactions 3. Express chemical equations 4. Use proportional reasoning to determine mole ratios 5. Solve a stoichiometry problem involving mass Additional questions to extend student critical thinking include: 1. What is the stability of biodiesel? (e.g., Changes occur in storage) 2. What components are needed to transport and deliver biodiesel? (e.g., Special rubber products) 3. How is the transesterification reaction a equilibrium reaction and what does that mean? 4. How would the reactants/products change if one reactant/product was changed? 5. Why is the concept of the equilibrium constant important to the biodiesel equation?; and ethically 6. Biodiesel might be a “better burning” fuel, but it is still emitting CO2, so what can be created to reduce the CO2 emissions?
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BIODIESEL IN THE AP CHEMISTRY CURRICULUM Recently, the College Board49 released a new framework for the AP Chemistry course emphasizing six Big Ideas that are reinforced by Enduring Understandings and Essential Knowledge supporting the course’s many Learning Objectives. The new course design also requires 25% of instructional time be laboratory-based with a minimum of 16 hands-on learning labs of which at least 6 are inquiry based. The Course and Exam Description49 notes that “to develop conceptual understanding, it is essential that the student can draw connections between concepts and engage in reasoning that combines essential knowledge components from across the curriculum framework”. For students to make such connections, they first need teachers to model the connections. Archer and Hughes50 note that if teachers’ initial instruction with high levels of involvement is characterized by clear descriptions and demonstrations of a skill, followed by supported practice and timely feedback, the teacher can systematically withdraw support, and the students move toward independent performance. One way to increase the likelihood of students making their own explicit connections is to use a central theme to teach content throughout a course. The components of the vertically aligned biodiesel lab presented earlier can serve as a theme that is revisited throughout an AP Chemistry course. During a typical AP class, the teacher’s discretion is used to provide examples illustrating the specific content that is covered. The authors recommend for an AP curriculum that the chemistry portion of this lab be performed when covering stoichiometry, thermodynamics, and/or titrations, but the central biodiesel theme can
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CHEMISTRY FINDINGS AND REFLECTION At the end of the summer RET experience, Behm stated, “I think it is important to show them [the students] the process. We’re not just going to hit and miss here, trial and error. We might get something; we might run into a mistake, but we’re going to approach this in a very systematic way”. Behm performed the biodiesel lab during a stoichiometry/chemical solutions unit in the following fall semester. Behm’s implementation of the biodiesel activity was successful during the activity and for many concepts covered later in the curriculum. Teaching the lab early in the year was a challenge because students did not H
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Table 3. Student Activity Feedback Form Comparison Survey Data from 2006−2010
on... this is research. You do something, and you’re doing it for the f irst time, and it doesn’t work perfectly so you’ve got to refine the process. I wish I’d had that experience as a high school student. I wish someone had shown me or at least told me. It happens. It happens a lot in the real-world”. Behm asked if an integrated STEM vertical lesson affected high school chemistry students’ skills and attitudes in relation to STEM subjects, and his data reflected that it did. Behm’s students asked more high quality questions and were engrossed with the idea of creating a usable product. Because of their interest in their biodiesel product, the students quickly acquired the desired skill set in the lab setting and had an increased positive attitude regarding STEM subjects (Table 3). Although not the primary focus of this article, data collected from the RET program between 2006 and 2010 supports the findings presented here. After exposure to real-world STEM lessons/labs such as the biodiesel production activity, student interest in science and engineering, knowledge about about STEM concepts, and confidence about their ability to use the material increased (Table 3). The students from the biology and chemistry classes described in this article are included in the overall data set from 2009 to 2010 (located in Table 3).
yet have background knowledge to fully appreciate the lab. Behm suggests that the activity should engage students in a deeper discussion and debate on the chemistry behind the biodiesel process before, during, and after the lab. The lab was also referenced during lessons on ionic and covalent bonding, when teaching solubility (NaOH does not readily dissolve in methanol), and as an introduction to organic compounds (e.g., free fatty acid, functional groups, and esterification). Overall the lesson was effective based on pre/post test scores. The pre- and posttests were identical and included three questions: (1) Why are stoichiometry and balancing equations important? Give an example.. (2) What types of chemical reactions are used in making biodiesel? Be specific and describe what happens. (3) Why is it important for researcher to explore new ways of producing biodiesel? What are differences in production methods? The pretest scores showed that 15% of the students scored greater than a 70% (8 of 53 students). The post-test scores showed 79% of the chemistry students scored greater than a 70% (42 of the 53 students). As with the biology algae lab, the biodiesel learning gains, based on the pre/post tests, were greater than the pre/post assessments on other units throughout the year. Positive student feedback included, “I liked learning about the dif ferences in oil f rom dif ferent restaurants” and “I liked how everyone’s oil didn't meet the requirements to be able to make biodiesel”. Student comments for improvement included, “I didn't like how the companies wouldn't give us oil for our project” and “I didn't like the math, but it wasn't too hard”. According to Behm, the biggest obstacle to the lab was a lack of separatory funnels used to wash the biodiesel (as the lack of this equipment significantly lowered biodiesel quality and yield). Even though some students were challenged by the concepts in the lab, it laid a foundation for many future topics. Most importantly, students were reintroduced to real-world applications that were used to create connections with other content. In an end of the year interview, Behm recalled, “You kind of appreciate the problem-solving component of research, and it happened when I was implementing my [biodiesel] lesson. I had the students making biodiesel and they had to go to purif y it, and wash and wash it. Well it proceeds to make a detergent, an emulsion, the biodiesel doesn’t separate, and the students are sitting there with a cloudy mixture of stuf f and I had to f igure out how to separate it. That was another step in the process, totally unanticipated. We had to f igure out how to break the emulsion and students were actually kind of mad about that. I told them there was a deficiency in the design of this process, guys, you’re so used to doing cookbook labs where you do this and this and then this happens and you move
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LIMITATIONS As stated earlier, there were challenges with creating the biodiesel itself and teaching the students the biology/ biochemistry and chemistry content connected to biodiesel production. Students lacked familiarity with equipment (e.g., probes) and concepts (e.g., oxygen vs growth), which led to difficulty with discussions and debates. However, there were other larger limitations to this study including that the biology lesson was only implemented once, whereas the chemistry lesson was implemented for several years. After the first year, there was never a chance for the chemistry students to have the integrated STEM base originally set forth in the biology lesson. As an action research project in two different classrooms, student pre/post data test scores, attitudes in lab settings, class questions, and projected college degrees were all taken into account in deciding on the success of the integrated STEM vertical curriculum. Specific pre/post test scores for each student was no longer available, and thus, significance testing on a per question basis was not possible. Moreover, this vertical lesson was intended for an Ohio high school, and was tailored to align with the curricula. Future work will include specific research questions with supporting data sets (e.g., What questions are the students asking in each of the classes during I
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ACKNOWLEDGMENTS The National Science Foundation, through a Research Experiences for Teachers (RET) grant, funded this work (#EEC 0808696) at the University of Cincinnati. Special gratitude is given to the following: (i) the students that participated in the activities and gave honest feedback; (ii) Anant Kukreti (PI) and Mingming Lu (CoPI) for their valuable guidance and research during and after the RET program; (iii) Angie Varca, AP chemistry teacher at Laramie High School, who provided a real-world view; and (iv) the numerous reviewers who helped to refine this manuscript.
the biodiesel activity?). To supplement this initial exploration, a new biology teacher would need to conduct the biodiesel activity and collect quantitative and qualitative data in order to understand the change that the biodiesel activity might have on the biology students. In turn, the chemistry teacher would need to continue the biodiesel activity and adopt/offer quantitative and qualitative methods that would mirror the biology collection.
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CONCLUSION AND IMPLICATIONS The biology/biochemistry algae lesson and chemistry transesterification lesson were successful in promoting students’ positive attitudes toward STEM, and the authors believe that it is the real-world applications of biodiesel that are at the heart of the success. In tandem with the real-world applications are the PBL, inquiry-based learning, engineering design, and SSI approaches that were used. The trend in data collected from 2006 through 2010 (Table 3) touts the connection that students make with topics such as biodiesel. Thus, the answer to the research questions is yes; real-world lab applications like the ones described heredo affect high school students’ skills and attitudes in relation to STEM subjects. Furthermore, the NGSS30 crosscutting concepts (e.g., Patterns, Cause and Effect) embedded in disciplinary core ideas and topics allow students to visualize how all STEM fields are interrelated and supplement each other, an incredibly powerful concept for students to grasp. A future research direction is to develop support for K−12 lesson planning and implementation of PBL, inquiry-based learning, engineering design, and SSI with specific interests on student outcomes. Implications of this work include a stronger integrated STEM vertical curriculum that could be implemented in an AP Chemistry program (or any STEM content area) to encourage and engage students in creating and investigating their own experiments within real-world applicability. The authors encourage all teachers to look to PBL, inquiry-based learning, engineering design, and SSI as means of engaging and motivating students in ways that truly change perceptions on topics. As Martin-Hansen asked, “Are we doing science or simply talking about it?”.51 To conclude, teachers can have a powerful influence over student perceptions of STEM and individual topics, and that authority should not be taken frivolously. Novak described that teachers can “influence the choice to learning meaningfully by the kind and organization of information presented, how it is sequenced, and instructional strategies employed”.3 One example is the content of biodiesel production that can allow for this meaningful learning, but there are other topics as well and all of them should be considered for exploration in order to supplement the notion that science disciplines are an interconnected web of concepts. No science discipline stands without the evidence of the other disciplines, and teachers can guide students that are debating and solving integrated problems.
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