Author: seceij

Abstract

This study examines the carbon footprint of a proposed biomass incinerator in Minneapolis and Saint Paul, Minnesota. This research was integrated as a service-learning project into the curriculum of an undergraduate differential equations course. Mathematical models were developed and analyzed to examine the local contribution of emissions to the atmosphere and the extent of land needed to offset incinerator emissions both in the short (daily) and long (yearly) term. [more] Our results show the sensitivity of atmospheric carbon content to the incinerator output rating, area and type of land dedicated for offsets, and atmospheric wind speed. The amount of managed land ranges from 7,000–20,000 hectares of land, or approximately the area of Saint Paul. The land requirements seem feasible in the context of the amount of available (unmanaged) land both locally and worldwide, but these requirements are diminished given the potential air quality effects resulting from biomass incineration.

Introduction

The Rock-Tenn paper recycling plant located in Saint Paul, Minnesota employs over 500 people and contributes significantly to the economic health of the greater Minneapolis-Saint Paul metropolitan area (Nelson 2007). The company initially had its thermal energy supplied by Xcel Energy, the local power provider. In late 2007, Xcel Energy decommissioned the plant that supplied Rock-Tenn’s thermal energy. Alternative sources of energy were needed to maintain the long-term sustainability of the recycling plant.

Refuse derived fuel (RDF) was a proposed alternative to provide energy for the recycling plant. This technique derives energy from the incineration of plant material, refuse, and compost (Nelson 2007). RDF is an example of bioenergy. Generally defined as the use of plant material to supply energy, bioenergy supplies 15 percent of the world’s energy needs (Lemus and Lal 2005). Bioenergy is an alternative energy to fossil fuels. Trees, through the process of photosynthesis, convert carbon dioxide into carbon, so any combustion of tree residue (and associated release to the atmosphere of this comparatively recently-fixed carbon) theoretically results in no net change of atmospheric carbon (Smith 2006).

Surrounding the Rock-Tenn plant are residential neighborhoods. In response to the proposed plan of the biomass incinerator, a grassroots organization, Neighbors Against the Burner, formed to oppose the incinerator, citing air quality effects on health (Pope et al. 2002) as one of its main objections. Based on the strong community response, in November 2008 the Saint Paul City Council passed a resolution against having the biomass incinerator be the energy source for Rock-Tenn. The Council advocated investigation of other alternative energy options, such as using biogas from anaerobic digestion (Saint Paul City Council 2008).

Augsburg College is a private, liberal arts college in Minneapolis, Minnesota, approximately three miles from the Rock-Tenn Recycling Plant. In spring semester 2008 as part of a semester-long research project for a course on differential equations, 11 students, with this author as the instructor, engaged in a service-learning project to investigate the atmospheric effects and carbon footprint of the proposed biomass incinerator. The project was integrated into the course content to provide a real-life example that had both civic and environmental connections. Two key research questions were addressed by the students:

1. How much do incinerator emissions elevate local atmospheric carbon?
2. What conditions need to be satisfied for carbon neutrality both short and long term?

For the purposes of this study, carbon neutrality implies zero net change in the atmospheric carbon content.

Methods

This study was integrated in the curriculum for a one-semester differential equations course. At the beginning of the term the instructor introduced the project objectives. The students formed teams to investigate the project objectives through construction and analysis of a mathematical model. The teams reported updates with the instructor throughout the semester. Additionally, a representative from Neighbors Against the Burner attended a class session to answer student questions and provide feedback. At the end of the term, students presented their results and wrote a report describing their results in the context of the mathematical, environmental, and civic dimensions of the project. The results presented in this study derive from these student projects.

Mathematical models

All mathematical models are formulated to measure the rate of change in atmospheric carbon content. Two overarching processes are assumed to affect this rate of change: emissions from the burner (increasing atmospheric carbon content) and biophysical processes that decrease atmospheric carbon. The following word equation describes this process:

Rate of change of atmospheric carbon =
Incinerator emissions – Biophysical processes

Emissions from the incinerator are assumed to occur at a constant rate, dependent on the emission type and incinerator output rating. To maintain carbon neutrality, we assume the existence of an active forest that removes carbon. With these assumptions, each team then had to quantify the appropriate mathematical model based on Equation 1. The mathematical models are qualitatively described below; additional mathematical descriptions are in the Appendix.

Emissions Contribution to Atmospheric Carbon. 

Emissions from the incinerator and subsequent dispersion into the atmosphere create a plume of incinerated material and gases. This model, derived from models of contaminant transport in fluids (Brannan and Boyce 2007; Falta Nao and Basu 2005), describes the rate that incinerated carbon enters the plume. The biophysical process term is assumed to be directly proportional to the wind speed versus higher wind speed values decrease the amount of carbon near the incinerator and increase the concentration of carbon in the plume. Outputs from this model could subsequently be used to quantify spatial distribution of carbon in the plume through diffusion, advection, and other atmospheric properties.

The incinerator emissions are inversely proportional to the smokestack output area, assumed to be 250 square meters for this study. The flow (in terms of volume per time) of emissions into the smokestack must equal the flow of emissions into the atmosphere. If the area of the smokestack increases, the rate of change of atmospheric carbon must decrease to maintain the constant flow of emissions.

Short and long term carbon neutrality. 

Long term atmospheric measurements of carbon dioxide over various ecosystems have shown the short and long term responses of ecosystems to carbon uptake through the dynamic processes of photosynthesis (conversion of carbon dioxide to simple sugars) and respiration (release of carbon dioxide to the atmosphere) (Baldocchi et al. 2001; Wofsy et al. 1993). Aggregated up to annual timescales, this balance between photosynthesis and respiration typically is negative (meaning the photosynthesis flux is stronger than all respiratory fluxes), indicating the ecosystem is a sink of carbon to the atmosphere. Diurnal fluctuations in temperature and moisture, seasonal variation, species composition, and plant species successional stage all contribute to an ecosystem being a given source or sink of carbon to the atmosphere (Baldocchi et al. 2001). The productivity of a forest (or its ability to decrease atmospheric carbon) can therefore be quantified with long-term records of net carbon uptake.

As previously stated, we assume the existence of a forest that will offset incinerator emissions. In our models this is represented by having the emissions term inversely proportional to the forest area. As forest area increases, emissions contribute proportionally less to atmospheric carbon because there are more trees to remove atmospheric carbon.

The biophysical process term was quantified in two different ways to describe short term (daily) and long term (yearly) carbon uptake. Short term carbon uptake was modeled with a dynamic, periodic term modeled after patterns of diurnal net ecosystem carbon exchange (Wofsy et al. 1993). Long term carbon uptake or forest productivity was assumed to occur at a constant rate, with values determined from Baldocchi et al. (2001).

Results

Figure 1 shows results of the influence of wind speed on atmospheric carbon content. As wind speed increases, local emissions decrease independent of burner output. Increasing the incinerator output rating o (measured in MBtu per hour) also increases atmospheric carbon content, inferring a higher concentration of carbon in the plume.

Figures 2a-b show model results of the daily temporal change in atmospheric carbon content. Vertical axis values in Figures 2a-b are scaled as a percent change from the initial atmospheric carbon content. Positive vertical axis values suggest that the incinerator is increasing atmospheric carbon dioxide levels, or a “carbon-positive” incinerator, whereas negative vertical axis values indicate the incinerator is “carbon-negative,” or that the forest removes additional carbon dioxide beyond incinerator emissions. The periodic behavior in atmospheric carbon results from the selection of a periodic function for the carbon uptake function (see the Appendix). Daytime has a stronger net carbon uptake, indicating trees in the forest are removing carbon from the atmosphere through photosynthesis, thereby decreasing atmospheric carbon content. As photosynthesis is a light-dependent reaction, during the night the forest is a source of atmospheric carbon.

Figure 2a reflects short term temporal emissions when the output rating of the boiler o is varied from 200 to 400 MBtu per hour. These output ratings were estimated from similar steam-producing systems as the one studied by the students (Energy Products of Idaho 2009). In all cases, it is assumed that there is an actively growing forest of 14,500 hectares (approximately the area of Saint Paul) to offset incinerator emissions. For an output rating of 400 MBtu per hour the atmospheric concentration is increasing at a constant rate of 10 percent per day, whereas for an output rating of 200 MBtu per hour the forest is large enough to reduce atmospheric carbon content by 10 percent per day.

Figure 2b shows the effect of changing the forest area on atmospheric carbon content. If the forest area is reduced to 10,000 hectares, then the incinerator becomes a source of carbon to the atmosphere with emissions growing at a rate of approximately 10 percent per day, indicating that the forest itself is not large enough to offset emissions from the plant. On the other hand, if the forest area is increased to 20,000 hectares, then the incinerator is “carbon negative,” decreasing atmospheric carbon concentrations approximately 10 percent per day.

Figure 3 shows the area of land that would need to be dedicated to maintain long-term carbon neutrality as a function of the output rating. As the output rating increases, a larger forest area will be needed to sustain carbon neutrality. The slope of the linear dependency in Figure 3 depends on the forest productivity (F) in removing carbon dioxide from the atmosphere. Different values of F result from the overall forest species composition (Baldocchi et al. 2001). The less productive forest (smaller values of F) will require a larger area to offset incinerator emissions.

Discussion

Evaluation of model results

A strong concern to the incinerator is the decrease in air quality in the neighborhoods surrounding the recycling plant. The results shown in Figure 1 qualitatively support this concern. Higher incinerator output ratings increase the amount of atmospheric carbon in the emissions plume. While atmospheric carbon decreases with increasing wind speed, conservation of mass infers that this carbon is dispersed to neighborhoods surrounding the incinerator.

Recent studies have shown linkages between public health and air quality (Pope et al. 2002; Zhang and Smith 2007). In addition to the carbon released through incineration, aerosols and other particulate matter may also be released into the atmosphere by incineration. While these other aerosols were not investigated in this study, the models presented here could easily be adapted to take these into consideration. Additionally, coupling this model to an atmospheric transport model could quantitatively describe increases in carbon or other aerosols and the spatial extent to neighborhoods around the incinerator.

Our results indicate that the amount of forest area needed to maintain carbon neutrality ranges between 7000–20000 hectares, depending on the type of species planted and the output rating (Figures 2 and 3). These estimates are a small fraction of land both locally and worldwide that could be dedicated to bioenergy. In Minnesota approximately 563,000 hectares of land could be rehabilitated to support bioenergy crops (Lemus and Lal 2005). Worldwide, the amount of land in need of restoration from degraded agricultural soils is approximately 1965 million hectares (Lemus and Lal 2005), which is a large proportion of the 2380 million hectares of land not classified as urbanized or protected (Read 2008). The total area of managed, or plantation, forests are 187 million hectares, consisting of 5 percent of worldwide forest area (Mead 2005).

Dedicating land to bioenergy crops helps to mitigate increasing levels of atmospheric carbon dioxide, restore soil organic carbon that were depleted from agricultural practices, and prevent erosion (Lemus and Lal 2005; Lal 2004; Sartori et al. 2006). In spite of these benefits and comparatively small area of land required to offset incinerator emissions, other factors not accounted for in our models would modify our estimates for the amount of land needed to offset emissions. First, technological advances will be required for their application, which may not be appropriate at all regional and local levels (Smith 2008). Second, bioenergy should be part of a suite of strategies targeted to mitigate climate change, which include the reduction of existing emissions through changes in consumption and improving agricultural efficiency (Smith 2008; Rhodes and Keith 2008). Third, life-cycle analyses for bioenergy crops (Adler, Del Grosso, and Parton 2007; Spartari, Zhang, and Maclean 2006) have shown a slight decrease in their mitigation potential when the growth and maintenance of the bioenergy crop (which requires energy) is taken into consideration. Additionally a recent study by Fargione et al. (Fargione et al. 2008) has quantified a substantial carbon “debt” incurred by clearing land for bioenergy crops. Further investigation into these factors is needed to refine and quantify the carbon footprint of the incinerator.

Evaluation of teaching and learning outcomes

Key learning outcomes of the project were to (a) develop and apply differential equation models to a contextual situation, (b) interpret results in the context of the carbon neutrality of the burner, and (c) provide valued recommendations based on the observations of the mathematical models.

The use of a service-learning-based project aligned well with both course learning objectives as well as the Augsburg College mission, which has a strong history in service learning (Hesser 1998). The students were given a survey to assess project outcomes in three categories: (a) overall learning (application and connection to course learning outcomes), (b) resource utilization (ability to complete the project independently), and (c) community connection (public acknowledgment of student efforts). The eleven students in the class responded to each category on a 5 point Likert scale. The average results were 3.9 (median 4) for the overall learning, 4.2 (median 4) for resource utilization, and 3.6 (median 4) for community connection. Students overall remarked positively about the service-learning project. One student remarked that “It was interesting to see real-world applications of math,” and another student commented “The project was an excellent way of learning how to put our concepts into a practical perspective, and it was also edifying to learn the nature of carbon neutrality.”

Based on the evaluations, it can be concluded from the student assessments that the first two outcomes were met (the construction, application, and interpretation of mathematical models). The lower ranking of the community connection category indicated not fully meeting the final objective. While students articulated recommendations on model results, a stronger connection to the relevant stakeholders in the issue (Neighbors Against the Burner and Rock-Tenn Recycling) could have been made. Multiple student evaluations expressed the desire for a tour of the recycling plant, or have more interaction with local community organizations beyond the mid-term visit. It would have been desirable to have a public forum of presentation of results, thereby increasing the visibility of the project in the college community.

This project has shown the qualitative contribution of the biomass incinerator to local atmospheric carbon content and the amount of land required to offset incinerator emissions. The project articulated the value of mathematical models and connected classroom learning to a civic and environmental issue.

Acknowledgments

The author would like to thank the students enrolled in the spring 2008 section of MAT 247: Modeling and Differential Equations for their diligent work and efforts; Mary Laurel True of the Center for Service, Work and Learning at Augsburg College; Benjamin Stottrup; and Tom Welna of Neighbors Against the Burner. Special thanks are expressed to the Barbara Farley, Vice-President of Academic Affairs at Augsburg College for conference travel support to present preliminary results at the Mathematical Association of America MathFest 2008.

About the Author

John Zobitz (zobitz@augsburg.edu) is an assistant professor of mathematics at Augsburg College in Minneapolis, Minnesota. John received his Ph.D. from the University of Utah in 2007, specializing in mathematical biology. Current research includes the development of mathematical models quantifying forest carbon uptake from automated data streams. He continues to find ways to intersect environmental mathematics with his mathematics teaching at all levels of the curriculum.

Appendix: Description of Mathematical Models

The quantity described in all models is the atmospheric carbon density (grams carbon per square meter, or g C m^-2), represented with the variable c. Models were expressed as a differential equation, and where appropriate, solved directly or with standard numerical techniques (Blanchard, Devaney, and Hall 2006). The initial condition (c₀) for all models assumes a fixed CO₂ mixing ratio of 385 parts per million by volume (National Oceanic and Atmospheric Administration 2009; Peters et al. 2007), assuming an air density of 44.6 mol m^-3(Campbell and Norman 1998) uniformly distributed up to 21.5 m above the ground surface. Energy units are expressed in MBtu, or a million British thermal units.

Model results were investigated in the context of the following key parameters:

1. Incinerator output rating o (MBtu hr^-1),
2. Atmospheric wind speed v (m hr^-1, expressed in all figures and results as miles hr^-1)
3. Forest area A (m², expressed in all figures and results as hectares)
4. Forest annual net carbon uptake or productivity F
5. (g C m^-2year^-1)

Emissions Contribution to Atmospheric Carbon

The model of the emissions contribution to atmospheric carbon was modified from models of contaminant transport in fluids (Brannan and Boyce 2007; Falta Nao and Basu 2005) with the following differential equation:

where c, t, o, and v are defined above, t is time (hours), α is a conversion factor from grams to pounds (453.59 grams pound^-1), ε is a conversion factor to determine the amount of carbon in carbon dioxide (0.2727 g C g^-1 CO₂), E is the emissions fuel type for wood (assumed to be 195 lbs CO₂MBtu^-1 [Palmer 2008]), o is the boiler output rating, S is the incinerator total smokestack area (assumed to be 250 m²). For a circular smokestack this would be a diameter of 17.8 m, and m0 is the initial atmospheric carbon volume (0.206 g C m^-3). Assuming the carbon dioxide concentration equilibrates rapidly to steady state (that is, dc/dt = 0), an expression can be determined that relates atmospheric carbon content c to the wind speed v, as shown in Figure 1 for different values of the output rating o.

Short- and Long-Term Carbon Neutrality

The short term carbon uptake was determined via the following differential equation:

where c, t, α, ε, E, and A are defined above. The periodic function represents the diurnal uptake pattern typically found in a forest (Wofsy et al. 1993). For this study, f₁ = 0.1 g C m^-2 hr^-1, f₂ = π/12 ≈ 0.262 hr^-1, f₃ = 0.524, and f₄ = 0.05 g C m^-2 hr^-1. The values of f₁, f₂, f₃, and f₄, were visually determined from data of the average diurnal uptake pattern for a coniferous forest during the peak summer carbon uptake period (Monson et al. 2002; Zobitz et al. 2007).

To investigate the long-term carbon footprint, the following model was used:

where all variables are defined above. Again assuming steady state dynamics (or no change in atmospheric carbon) a linear equation between A and o can be formulated and is represented for different values of F in Figure 3.

References

Adler, P.R., S.J. Del Grosso, and W.J. Parton. 2007. “Life-cycle Assessment of Net Greenhouse-Gas Flux for Bioenergy Cropping Systems.” Ecological Applications 17 (3): 675–691.

Baldocchi, D., et al. 2001. “FLUXNET: A New Tool to Study the Temporal and Spatial Variability of Ecosystem-Scale Carbon Dioxide, Water Vapor, and Energy Flux Densities.” Bulletin of the American Meteorological Society 82(11): 2415–2434.

Blanchard, P., R.L. Devaney, and G.R. Hall. 2006. Differential Equations. 3rd ed. Belmont, CA: Thomson Brooks/Cole.

Brannan, J.R., and W.E. Boyce. 2007. Differential Equations: An Introduction to Modern Methods and Applications. Hoboken, NJ: John Wiley & Sons.

Campbell, G.S., and J.M. Norman. 1998. An Introduction to Environmental Biophysics. 2nd ed. New York: Springer.

Energy Products of Idaho. 2009. “Energy Output.”
http://www.energyproducts.com/energy1.htm (accessed
June 1, 2009).

Falta, R.W., P.S. Nao, and N. Basu. 2005. “Assessing the Impacts of Partial Mass Depletion in DNAPLE Source Zones I: Analytical Modeling of Source Strength Functions and Plume Response.” Journal of Contaminant Hydrology 78(4): 259–280.

Fargione, J., et al. 2008. “Land Clearing and the Biofuel Carbon Debt.” Science 319: 1235–1238.

Hesser, G. 1998. “On the Shoulders of Giants: Building on a Tradition of Experiential Education at Augsburg College.” In Successful Service-Learning Programs: New Models of Excellence in Higher Education, ed. E. Zlotkowski. Bolton, MA: Anker Publishing Company.

Lal, R. 2004. “Soil Carbon Sequestration Impacts on Global Climate Change and Food Security.” Science 304: 1623–1627.

Lemus, R., and R. Lal. 2005. “Bioenergy Crops and Carbon Sequestration.” Critical Reviews in Plant Sciences 24: 1–21.

Mead, D.J. 2005 “Forests for Energy and the Role of Planted Trees.” Critical Reviews in Plant Sciences 24: 407–421.

Monson, R.K., et al. 2002. “Carbon Sequestration in a High-Elevation, Subalpine Forest. Global Change Biology 8 (5): 459–478.

National Oceanic and Atmospheric Administration, Earth System Research Laboratory. “CarbonTracker” 2009. http://carbontracker.noaa.gov (accessed June 1, 2009).

Nelson, C. 2007. Renewing Rock Tenn: A Biomass Fuels Assessment for Rock-Tenn’s St. Paul Recycled Paper Mill (Minneapolis, MN: Green Institute). http://www.greeninstitute.org/media/documents/RenewingRock-Tenn_BiomassFuelsAssessment_GreenInstitute_
032907.pdf (accessed December 14, 2009).

Palmer, G. 2008. Biomass Emissions Data. Personal communication to Rock-Tenn Community Advisory Panel (January 14, 2008).

Peters, W., et al. 2007. “An Atmospheric Perspective on North American Carbon Dioxide Exchange: CarbonTracker.” Proceedings of the National Academy of Sciences 104 (48): 18925–18930.

Pope, C.A., et al. 2002. “Lung Cancer, Cardiopulmonary Mortality, and Long-term Exposure to Fine Particulate Air Pollution.” Journal of the American Medical Association 287(9): 1132–1141.

Read, P. 2008. “Biosphere Carbon Stock Management: Addressing the Threat of Abrupt Climate Change in the Next Few Decades: An Editorial Essay.” Climatic Change 87: 305–320.

Rhodes, J.S., and D.W. Keith. 2008 “Biomass with Capture: Negative Emissions Within Social and Environmental Constraints: An Editorial Comment.” Climatic Change 87: 321–328.

Saint Paul City Council. 2008. Resolution 08-1281, November 19, 2008.

Sartori, F., et al. 2006. “Potential Soil Carbon Sequestration and CO₂ Offset by Dedicated Energy Crops in the USA.” Critical Reviews in Plant Sciences 25: 441–472.

Smith, P. 2006. “Bioenergy: Not a New Sports Drink, but a Way to Tackle Climate Change.” Biologist 53(1): 23–29.

Smith, P., et al., 2008. “Greenhouse Gas Mitigation in Agriculture.” Philosophical Transactions of the Royal Society B: Biological Sciences 363 (1492): 789–813.

Spartari, S., Y. Zhang, and H.L. Maclean. 2006. “Life Cycle Assessment of Switchgrass- and Corn Stover–Derived Ethanol-Fueled Automobiles.” Environmental Science and Technology 39: 9750–9758.

Wofsy, S.C., et al. 1993. “Net Exchange of CO₂ in a Mid-Latitude Forest.” Science 260: 1314–1317.

Zhang, J., and K.R. Smith. 2007. “Household Air Pollution from Coal and Biomass Fuels in China: Measurements, Health Impacts, and Interventions.” Environmental Health Perspectives 115: 848–855.

Zobitz, J.M., et al. 2007. “Partitioning Net Ecosystem Exchange of CO₂ in a High-Elevation Subalpine Forest: Comparison Of A Bayesian/Isotope Approach to Environmental Regression Methods.” Journal of Geophysical Research-Biogeosciences 112, G03013, doi:10.1029/2006JG000282.

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Abstract

Pre-service and in-service elementary teachers tend to have poor attitudes and beliefs about science that stem from their own early science-related experiences. The development of positive dispositions toward science among pre-service teachers is problematic but essential if we are to improve science education. Attitudes will affect behavior and positive attitudes among pre-service teachers will lead to good learning and subsequently to good science teaching. Previous studies suggest college science courses that contain elements of inquiry-based learning, practical application to teaching, and engagement with broader real-world issues can affect positive change in these dispositions. [more] Here, I report on the efficacy of a new biology course at Longwood University in improving science dispositions among pre-service teachers. The course, modeled on a SENCER (Science Education for New Civic Engagements and Responsibilities) approach, engages students in biological concepts using focal topics that involve timely, complex, and biologically relevant issues confronting society. Four semesters of assessment data demonstrate a favorable change in students’ attitudes toward science, science teaching, and engagement in broader civic issues after completing the course.

Introduction

Wanted: College and university science teachers wishing to become engaged in a comprehensive, important, and potentially transforming educational movement. Those who accept the challenge will join with K–12 teachers in a quest to give every American an essential understanding of the physical and biological processes that characterize our world, and to nurture curiosity and scientific habits of mind. In the process, all participants will experience change and renewal.

This opening paragraph of “College Pathways to the Science Education Standards” (Siebert and McIntosh, 2001), both highlights the critical need for systematic consideration of science education in higher education but also identifies one of the greatest obstacles to holistic change: the cyclic nature of our educational systems. Teachers often teach as they were taught (Watters and Ginns, 2000), and thus meaningful and positive change is required not only to improve scientific understanding of all citizens but also to affect the “pipeline” that develops future K–12 teachers.

Pre-service and in-service elementary teachers, in general, tend to have poor attitudes and beliefs about science and their capacities to be effective teachers of science (Stevens and Wenner, 1996), and many experienced teachers report feeling uncomfortable and unqualified to teach science (Kahle, Anderson, and Damjanovic, 1991). Research suggests that these attitudes develop as a result of their own science-related experiences in elementary and high schools (deLaat and Watters, 1995) and support the teacher preparation pipeline problem: a student’s interest in pursuing science is shaped by experiences at a young age and his/her most frequent exposure to science is through those teachers. While these pre-service and in-service teachers often have a love for the profession of teaching, they may lack a passion for or real connection to the science content. Given this situation, the development of positive dispositions towards science and science teaching among pre-service teachers is problematic (Watters and Ginns, 2000).

If we seek to change this cycle by impacting the preparation of our future K–8 teachers in their science courses in higher education, we must accept some of the constraints of our own systems. In most college and university science departments, courses are taught by disciplinary experts who may have little or no formal training in teaching or science education. As such, at the college level we have the same issues as at the K–8 levels but in reverse: faculty with a love for the content but who may not be prepared to or comfortable with modeling and teaching pedagogical approaches for these teacher candidates. How then can we seek meaningful change in the preparation of K–8 teachers while working within the higher education systems, neither overwhelming faculty with proposed changes nor selling short our future teachers on the content and context they need to successfully teach their own students?

My research in this area supports the utility of the SENCER approach (Science Education for New Civic Engagements and Responsibilities) as a way to reform science courses in higher education and positively impact teachers. SENCER (2009), a national initiative funded by the National Science Foundation and housed at the National Center for Science and Civic Engagement at Harrisburg University of Science and Technology, seeks to improve learning and stimulate civic engagement by teaching science through complex, largely unsolved civic issues that interest large numbers of students. In this paper I present survey data collected in a SENCER-styled course for pre-service teachers at Longwood University. The survey was designed to assess the efficacy of this course in improving dispositions that lead to increased student learning of science concepts, greater confidence in teaching science, and enhanced engagement in broader civic issues. The underlying idea of this study is that attitudes will affect behavior and that positive attitudes among pre-service teachers will lead to good learning and subsequently to good science teaching.

Methods

Institutional context
Longwood University has a long tradition of developing teachers, and until 1975 was an all-female institution with a predominant focus on teacher education. Today, pre-service teachers continue to make up the largest major program on campus (approximately 750 of 3900 undergraduates). The home for these pre-service teachers is the Liberal Studies program in the Cook-Cole College of Arts and Sciences. This program seeks to provide a strong Liberal Arts content background to pre-service teachers before they begin their formal training in education. In addition to their required General Education science course, students within the Liberal Studies program who are seeking elementary licensure (grades K–6) are required to take four science courses: one two-hour physics course, one two-hour chemistry course, one three-hour earth science course, and one four-hour biology course. Students electing to obtain certification to teach science at the middle school level (grades 6–8) have the additional requirement of selecting General Chemistry 101 as their general education science requirement.

Course context
The Fundamentals of Life Science, Biology 114, is a required science course for all of Longwood’s Liberal Studies majors and is the only life science course they are required to complete in preparation for their teaching careers. As a four-credit hour course, students participate in three hours of lecture and two hours of laboratory each week. The course was first offered in the fall of 2004 following a curriculum change to science requirements in the major; prior to this term, students seeking K–8 teaching licensure were required to complete four-credit courses in zoology and botany. These courses were taught using a traditional lecture-lab format. As the primary instructor for the new course, I had the opportunity to design a new course model.

Building on student feedback from previous courses, relevant pedagogical research on the effectiveness of topic-focused and inquiry-based approaches (Korb, Sirola and Climack, 2005; Crowther and Bonnstetter, 1997), and my department’s involvement in the SENCER program, I structured Biology 114 around a number of focal topics. These topics involve timely, complex, and biologically relevant issues confronting society. Students are engaged in these topics from the start and are required to reflect on and inquire about these issues throughout the course. For example, we spend several weeks engaging the topic of cancer, a subject that most students consider interesting and important and one with a rich civic context. To build student interest in the topic, they are assigned context readings beforehand. These may be cancer survivor stories or articles on new treatment technologies. Along with discussions and reflective writing assignments over these readings, students analyze recent trends in cancer rates and are asked to generate hypotheses explaining them. Students then test their hypotheses, in effect, by writing a brief research paper that explores recent research related to the hypotheses. While engaging this topic and its broader impacts on society, students learn important biological concepts such as cellular chemistry, cell division, DNA structure and function, and cell regulation.

Other focal topics follow to sustain student engagement and interest in class and in their learning; these include genetic engineering and the stem-cell debate, HIV-AIDS, drug and alcohol abuse, human overpopulation, and the biodiversity crisis. Each topic is introduced with context readings and analysis of relevant statistics and data. Interest is sustained through additional readings, discussions, relevant news clips and videos, and short reflective writing assignments. While these focal topics function as umbrellas under which students learn much basic science content and make connections to live as citizens, they are also required to synthesize the material in the specific context of their chosen profession.

Students are further prepared for work in their future classrooms by participating in active, inquiry-based laboratories and through a novel assignment that requires them to reflect on biological content covered throughout a focal topic and then locate relevant K–8 Virginia Standards of Learning (SOLs)that apply to the specific content (Virginia Department of Education, 2007). This encourages students to consider and make connections between the college-level concepts learned in class and the K–8 content they will be teaching in the future.

Assessment tools
To evaluate change in pre-service teachers’ dispositions I constructed a survey composed of twenty statements designed to assess attitudes related to science and the teaching of science at the K–8 level (Table 1, below). Students were asked to reflect on their level of agreement with each statement and respond using a Likert scale (Edwards, 1957), where 1 = strongly disagree, 3 = neutral, and 5 = strongly agree. The twenty survey statements were constructed around four categories focusing on different dispositions and capacities. Statements 1–5 addressed students’ level of confidence in their science content knowledge, science process skills, and ability to teach scientific concepts. Statements 6–10 assessed students’ awareness of the importance of learning and teaching science in a greater societal context. Statements 11–15 assessed students’ appreciation of scientific contributions to society and the importance of scientific research. Statements 16–20 addressed students’ feelings of achievement related to their personal development in how they think about science and science teaching. Additionally, students were solicited for comments regarding their feelings or attitudes about science in general and their ability and desire to teach science in their future classrooms.

Participants
The assessment plan and protocol was approved by the Human and Animal Subjects Research Review Committee of Longwood University prior to the initiation of data collection and was renewed annually. Students were informed of the study, assured the anonymity of their responses, and provided the option to participate. The disposition assessment and solicitation of comments were administered on the first day of class and again during the last week of class for four consecutive semesters (fall 2005, spring 2006, fall 2006, spring 2007). Of 309 students enrolled in the course during this period, 91 percent (n = 281) participated in the pre-course assessment and 84.5 percent (n = 261) in the post-course assessment. Of the participants completing the pre-assessment, 12.8 percent (n = 36) provided pre-assessment comments while 15 percent (n = 39) provided post-assessment comments. The student population in Biology 114 was predominantly underclassmen and female (95.8 percent). The majority of participants (84.6 percent, n = 238) planned to start a teaching career in the K–6 grade levels.

Analysis
Survey data were pooled from all four semesters into pre- and post-assessment groups. For this report on the project to date, I calculated means and standard errors of student responses to nineteen survey statements. One survey statement (number 16) was omitted from all analyses due to relevancy of the statement to the survey population. I also compiled summary data by disposition category and report pre- and post-assessment means of scores and the mean change in pre- and post-assessment scores by category.

Results

Pre-service K–8 teachers participating in the Biology 114 pre- and post-course disposition assessments demonstrated a favorable change in their general attitudes toward science and science teaching. The mean of scores reported by students increased for all nineteen survey statements between the pre- and post-assessment (Figure 1). The largest positive mean change in response between pre- and post-assessment occurred in the personal achievement category (mean ∆ = 1.13), indicating participants felt more positive in their personal development of how they think about science and science teaching after completing the course (Figure 1). The second largest mean change in student response was in the category addressing students’ level of confidence in their science content knowledge, science process skills, and ability to teach scientific concepts (mean ∆ = 0.88).

I also found consistent improvements between pre- and post-assessment comments regarding participants’ feelings or attitudes about science in general and their ability and desire to teach science in their future classrooms. Students also responded favorably in post-assessment responses to the SENCER-style approach of the course. A representative sample of these comments is provided in Table 2. During the pre-assessment, 6.4 percent (n = 18) of participants indicated a career plan that included obtaining middle-school science licensure; in the post-assessment, that percentage had increased to 8.9 percent (n = 23).

Discussion

Recent research suggests that college science courses that contain elements of inquiry-based and hands-on learning (Palmer, 2001), practical application to teaching (Korb, Sirola and Climack, 2005), and engagement with broader real-world issues (Middlecamp, Phillips, Bentley, and Baldwin, 2006) affect positive change in undergraduate students’ dispositions toward science. This preliminary study of the outcomes of Biology 114, a course that incorporates each of these elements in a SENCER teaching approach, lends further support to these positive effects on pre-service teachers. Though the recorded changes were uniformly positive in four semesters of data collection, the means and degrees of change varied among disposition categories.

Students’ self-reported feelings of achievement related to their personal development in how they think about science and science teaching (statements 17–20) showed the most change, while student confidence in their science content knowledge, science process skills, and ability to teach scientific concepts (statements 1–5) showed the second greatest change. These results demonstrate the course was successful at improving students’ confidence in their science abilities, which should translate into a more positive attitude toward teaching science in their own classrooms (Young, 1998).

Interestingly, though still positive overall, there was less cumulative change in dispositions related to students’ awareness of the importance of learning and teaching science in a greater societal context (statements 6–10) and in dispositions related to appreciation of scientific contributions and the importance of scientific research (statements 11–15). Mean scores for pre-assessment responses to statements in these two disposition categories were higher than were the mean scores for pre-assessment responses in the former two categories. Relatively high responses to pre-assessment statements in these categories suggest students entered the course with at least a perceived awareness and appreciation for the contributions and relevance of science. Exposure to intense media coverage of many controversial and capacious issues involving science may foster student perceptions of being informed and aware of these specific issues. This response trend may also be related to students’ previous science experiences, a possible covariate that will be explored in future analyses.

The amount of change between pre- and post-assessment mean of scores reported by students increased over the course of four semesters. In fact, in consecutive semesters, students responded increasingly more positively to post-assessment survey statements in all four disposition categories. This temporal trend of improvement in science dispositions likely reflects the time required to develop and refine course content and context in this SENCER model. This consideration is important for others wishing to adopt this pedagogical approach.

Informal discussions with students further support post-assessment comments that students appreciated making science content relevant to teaching and to everyday living experiences: they find worth in studying science when they recognize it relates to their life and profession (Korb, Sirola and Climack, 2005). Many students found it challenging to match course content to K–8 SOLs and then provide a rationale for those connections, especially with the more abstract or complex college-level concepts that had no obvious K–8 counterpart. As these assignments had direct connection to their future teaching, students found them useful and helpful, even if difficult (Table 2). For an instructor with little formal training in teaching methodologies, these structured assignments provided an intentional link between content and teaching; yet by placing the burden on the students to make and justify their own connections to elementary course content, I was able to maintain class focus on subject content and context instead of on teaching methods.

Future plans for this endeavor include a continuation of the assessments in Biology 114 and discussions with colleagues on expanding the use of the pedagogical methods discussed here to other science courses required in the Liberal Studies major program. Also, as this dataset grows, I will examine the roll of covariates on assessment responses; factors such as the number of previous science courses the student has taken prior to Biology 114 and the grade level the student plans to teach may function to determine the degree of change in assessment responses. Additionally, I intend to broaden the use of these assessments to test the hypothesis that dispositions toward science, science teaching, and civic engagement continue to improve, first, as pre-service teachers move into their pre-professional education training and second, as new teachers gain actual experience in their own classrooms.

Biology 114 continues to evolve as a course as I modify content and context to reflect new trends and research in focal areas and discover alternative ways to engage future teachers in biology and science teaching. Future teachers who enter the workforce with an appreciation of and sense of excitement for the sciences will help to break the cycle and ensure that our children leave school with a better understanding of our world and the immense challenges and opportunities we face.

Acknowledgments

This research was supported through an Educator Preparation Program Effectiveness Grant from Longwood University’s Professional Educator’s Council. I thank my colleagues, Dr. Enza McCauley, for providing her guidance and expertise in the development of the assessment tool, and Dr. Alix Fink, for her encouragement and advice on the challenges and rewards of teaching through focal topics.

About the Author

Dr. Mark Fink is an Associate Professor of Biology at Longwood University. His research at Longwood focuses on basic and applied questions relating to the ecology of birds. His current research focuses on aspects of avian reproductive ecology and understanding the impacts of habitat alteration on reproductive success and population dynamics of early-successional birds of the Virginia Piedmont.

He is also interested in pedagogical questions relating to how undergraduate students, especially pre-service teachers, best learn science concepts and appreciation. He is currently examining the influence of existing science courses at Longwood University on dispositions toward science and science education among pre-service and in-service K–8 teachers.

Dr. Fink has been at Longwood since 2001. He has a doctoral degree in biology from the University of Missouri and Master of Science degree in wildlife and fisheries science from Texas A&M University.

References

Crowther, David T. and Ronald J. Bonnstetter. 1997. “Science Experiences and Attitudes of Elementary Education Majors as They Experience an Alternative Content Biology Course: A Multiple Case Study and Substantive Theory.” In Proceedings of the 1997 Annual International Conference of the Association for the Education of Teachers in Science, Peter A. Rubba, Patricia F. Keig, and James A. Rye, editors, 177–206. Cincinnati, OH: Association for the Education of Teachers in Science.

deLaat, Jenny and James J. Watters. 1995. “Science Teaching Self-Efficacy in a Primary School: A Case Study.” Research in Science Teaching 25 (4): 453–464.

Edwards, A.L. 1957. Techniques of Attitude Scale Construction. New York: Appleton-Century-Crofts.

Kahle, Jane Butler, Andrea Anderson, and Arta Damnjanovic. 1991. “A Comparison of Elementary Teacher Attitudes and Skills in Teaching Science in Australia and the United States.” Research in Science Education 21(1): 208–216.

Korb, Michele A., Christopher Sirola, and Rebecca Climack. 2005. “Promoting Physical Science to Education Majors: Making Connections between Science and Teaching.” Journal of College Science Teaching 34 (5): 42–45.

Middlecamp, Catherine Hurt, Margaret F. Phillips, Anne K. Bentley, and Omie Baldwin. 2006. “Chemistry, Society, and Civic Engagement (Part 2): Uranium and American Indians.” Journal of Chemical Education 83(9): 1308–1312.

Palmer, D.H. 2001. “Factors Contributing to Attitude Exchange Amongst Preservice Elementary Teachers.” Science Teacher Education 86: 122–138.

SENCER: Science Education for New Civic Engagements and Responsibilities. 2009. http://www.sencer.net (accessed December 12, 2009).

Siebert, Eleanor Dantzler and William J. Siebert, eds. 2001. College Pathways to the Science Education Standards. Arlington, va: NSTA Press.

Stevens, Carol and George Wenner. 1996. “Elementary Preservice Teachers’ Knowledge and Beliefs Regarding Science and Mathematics.” School Science and Mathematics 96(1): 2–9.

Watters, James J. and Ian S. Ginns. (2000). “Developing Motivation to Teach Elementary Science: Effect of Collaborative and Authentic Learning Practices in Preservice Education. Journal of Science Teacher Education 11(4): 277–313.

Virginia Department of Education. 2007. “The Virginia Standards of Learning, K–12.” http://www.doe.virginia.gov/VDOE/Instruction/sol.html (accessed December 12, 2009).

Young, Tricia. 1998. “Student Teachers’ Attitudes Towards Science (STATS).” Evaluation and Research in Education 12(2): 96–111.

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