Academic journal article Journal of College Science Teaching

Principles, First and Foremost: A Tool for Understanding Biological Processes

Academic journal article Journal of College Science Teaching

Principles, First and Foremost: A Tool for Understanding Biological Processes

Article excerpt

Distinguishing between matter and energy is a difficult task for college students, yet one that has implications beyond their science coursework. Issues of recycling, conservation of natural resources including energy, and weight loss all have conservation of matter and energy as their foundation. Students often fail to realize the power of using a few foundational principles, such as conservation of matter and energy, rather than relying on a multitude of facts in understanding the world around them. We developed an instructional model that focused on using principles first, foremost, and as tools in a wide variety of contexts. We focused especially on changes in matter and energy in processes that involve carbon in living systems. We implemented this model in a test group of multiple sections of an integrated science course for preservice elementary teachers who were nonscience majors. We compared the test group performance to a comparison group of science majors who were taught with other instructional models. The gain in proficiency was much greater in the test group than in the comparison group. Our results suggest that principle-based reasoning can lead to substantive improvements in students' understanding of core scientific concepts.

All science disciplines have their own "big ideas," which are the basis of course curricula, learning materials, and assessments. Underlying these disciplinary big ideas are a few principles that cross disciplines. Conservation of matter and conservation of energy are such principles. Although conservation is a disciplinary big idea in chemistry, it is also a foundational big idea that underlies biology, geology, and climatology. In life science, for example, conservation of energy is exemplified in the transfer of energy in a food chain, with decreasing amounts of chemical energy in food balanced by increased amounts of heat energy transferred to the environment. In geology, conservation of matter is the basic concept of the rock cycle, with atoms changing in location and association with other atoms but not being destroyed.

The idea that neither energy nor atoms are created or destroyed in physical and chemical changes seems straightforward, but a conceptual understanding of these principles is more problematic than many college faculty realize. College students struggle in distinct ways with these concepts. Some students believe that atoms, and similarly energy, can be used up. In other words, there is no reason to account for atoms or energy in physical or chemical changes because they can cease to exist. Other students believe that atoms can change into energy. A lack of conceptual understanding of conservation of matter and energy prevents students from using these principles to reason scientifically when faced with new problems.

These difficulties become especially confounded in biological processes (e.g., photosynthesis, cellular respiration, and biosynthesis) because the matter under consideration is often food, which serves as both a source of energy and a source of molecules for building the structure of living things. Even college biology students have difficulty in reasoning scientifically. For example, science majors incorporated many more facts into their responses about biological processes at the end of biology courses, but their ability to apply basic conservation principles improved only marginally (Hartley, Wilke, Schramm, D'Avanzo, & Anderson, 2011). A core problem in these responses is students not recognizing the difference between facts and guiding principles with which one can reason scientifically (Parker et al., 2012).

Yet it is essential for all college students, science majors or not, to achieve this conceptual understanding that enables them to use scientific reasoning when faced with situations in everyday life. Decisions regarding personal health and consumer choices often involve an understanding of the permanence of atoms (e. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.