Rationale
Questions
Most educators have (at some point in their career), been challenged by a student wishing to know why a given concept is important to learn. The question, “Why do we have to learn this” (which may seem as an attempt to derail or delay the day’s classwork) is, in my estimation, always appropriate and deserving of an honest and complete answer. The “Question” is particularly important as it challenges me to genuinely analyze why I think a given concept merits my student’s attention and intellectual engagement. I take great care when answering this question (and all other queries that challenge authority and accepted dogma), because it is the tenor of my (our) responses that fosters the kind of inquisitive, informed, and critical intellects needed in a world that is in a state of continual flux. These habits of mind are especially important in the science classroom where new technologies and ongoing research alter (and in many instances supplant) accepted scientific theories and beliefs. They are equally salient in our discourse on environmental policy where increasing populations and expanding economies threaten the sustainability of our ecosystems.
Recent discoveries of untapped deposits of oil and natural gas, along with new technologies that allow for the (relatively profitable) extraction and processing of these deposits have changed the outlook for the long range availability of fossil fuels. The realization that we may not run out of these environmentally damaging fuels in our lifetime debunks existing theories on the end of the era of fossil fuels and reframes the global discourse on the relation between energy usage and environmental policy (Mann 2013). Although the world’s major economies have recently undertaken policies that would limit greenhouse gas emissions, (European Commission 2015) many of these efforts were driven by the belief that conservation was needed because we would at some point deplete our fossil fuel reserves (Grätzel 2005). That is no longer our reality. We are now faced with a new set of questions
How do we meet our increasing energy requirements in ways that are economically viable and mindful of our responsibility to the environment?
The new reality makes it more difficult to propose responsible energy policies that prioritize our environment over economic growth. We are therefore at an even more dangerous point in our collective history because our ever-increasing global population and the growth of newly developing economies will likely double our energy needs in the next half-century. Our newly discovered reserves of (seemingly limitless) fossil fuel reserves lead one to ask:
Why should we curtail our use of fossil fuels and use less efficient, more expensive renewable energy sources when fossil fuels are readily and cheaply available?
These and (other questions) will frame the discussions in my chemistry class as we consider our responsibilities as stewards of the environment. They are important questions because climate change is real, and my students will need to understand the risks we face if we continue present energy policies. More importantly, they will need to determine their roles and responsibilities as members of the global community. The unit will be especially important as it will provide a forum in which I can begin a discussion of environmental responsibility in a class where these issues are not usually discussed.
I teach chemistry and environmental science at the Philadelphia High School for Girls. We are a special admission school with a population of approximately 1400 girls. Students admitted to the school must have a minimum GPA of 3.5, excellent behavior records, and have advanced or proficient scores in state standardized assessments. The school is relatively diverse with 68% African American, 15% Asian, 12% Latino, 4% White, with a small percentage of African, and Middle Eastern students. While most of the students have outstanding academic records, many have had little or no comprehensive science classes during their middle school years. This has occurred because many schools in our district (in response to the pressures of state mandated standardized assessments), have focused their efforts on mathematics / literacy skills at the expense of a rich science curriculum. As a result, few have been exposed to science as a way of making sense of the world in which they live or (more importantly) of using science to answer the difficult questions our society faces.
The Common Core Literacy Standards (Common Core Initiative 2009), encourages teachers to provide opportunities for students to analyze and evaluate social and cultural issues that impact their lives. Doing so in the science classroom helps students to use science to resolve difficult problems in the real world (Mochizuki and Bryan 2015).
Energy is addressed as a general concept throughout my chemistry curriculum; however, the environmental consequences of current energy policies are not adequately addressed. An exploration of existing and future energy sources would help expand the range of the classroom discourse on energy while providing a forum in which to discuss how new energy sources can solve society’s energy needs in a sustainable manner. Although I teach energy and its transformations as part of the chemistry curriculum, I did not have a deep conceptual understanding of how light energy is converted to electrical energy. Learning more about these electrochemical processes has greatly expanded my knowledge of solar energy and (in particular) the chemistry of solar cells.
Students will be able to use the concept of electron transfer to analyze the chemical reactions plants use to transform radiant energy to chemical energy. They should be able to evaluate the chemistry of fossil fuels and evaluate the effect of their continued use on the environment. They will also be able to assemble and measure the efficiency of a dye-sensitized solar cell.
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