Students may think of microbes -- sometimes called germs -- as something they want to wash off carefully or just avoid completely. But some microbes feed us, recycle our trash, or even keep us healthy! In this class students grow microbes on purpose, and conduct experiments about our tiniest living neighbors. Required background research and lab reports are important parts of this course.

We begin with something like one of the following questions: Where would you expect to find the most microbes? What is the best way to grow the most microbes? How does cabbage + salt turn into sauerkraut? Which plate has the most microbes (from a set of prepared plates)? Which plate of microbes came from which location (from a set of prepared plates and a list of locations sampled)?

From there, students generate questions about microbes -- what do they eat? how big are they? how long can they live? etc. -- and questions about microbiological laboratory techniques -- what's the best way to sample the microbes in tap water? How do you count or measure organisms that are so small? etc. -- and questions about relations between humans and microbes -- are some microbes good for you? how do microbes make you sick? etc.

Then some readings are introduced that are relevant to the students' primary interests in microbes. The assignment emphasizes generating questions, finding answers to some, and thinking through ways of finding answers to others. Then there is a discussion of experimental questions -- what that means, how you recognize one -- and the ideas are applied to a list of students' questions from the whole class to date. That generates a list of students' experimental questions about microbes. We then go through a process of alternating background research and discussion of what information students uncover, and how, and strategies for research, as well as narrowing down the experimental questions. Ultimately a question is selected -- sometimes for the whole class, sometimes for small groups, and sometimes for individual students, depending on the group and time constraints.

Presentations follow, where students learn to both support and critique their classmates' questions, research, experimental designs, data display, and analysis. Then the process is reiterated, this time with more complex subject-matter, more in-depth research, more involved laboratory techniques, quantitative data collection, and more independent work on the part of the students.

Both projects culminate in lab reports, which are revised, sometimes repeatedly, using teacher and students comments as a guide.

Depending on the schedule and pace of the group, other topics in microbiology are introduced and discussed in parallel with the students' research. Often these topics follow student interest, and items in the news. Some topics are generally included each semester, such as the 3-domain versus 5-kingdom trees of life, evolution of antibiotic resistance, the human microbiome, etc.

Alcamo, I. E., Alcamo, I. E., Elson, L. M., & Elson, L. M. (1996). The microbiology coloring book. New York, NY: HarperCollins College Publishers. oli and the new science of life. New York: Pantheon Books.
Alexander, S. K., & Strete, D. (2001). Microbiology: a photographic atlas for the laboratory. San Francisco: Benjamin Cummings. Benson, H. J. (1967). Microbiological applications: a laboratory manual in general microbiology.. Dubuque: Wm. C. Brown. Black, J. G. (2004). Microbiology: principles and explorations (6th ed.). Hoboken, NJ: John Wiley. Byrd, J. J., & Powledge, T. M. (2006). The complete idiot's guide to microbiology. New York: Alpha Books. DeSalle, R. (1999). Epidemic!: the world of infectious diseases. New York: The New Press :. Dixon, B. (1994). Power unseen: how microbes rule the world. Oxford: W.H. Freeman. Harold, F. M. (2001). The way of the cell: molecules, organisms, and the order of life. Oxford: Oxford University Press. Hudson, B. K., & Sherwood, L. (1997). Explorations in microbiology. Upper Saddle River, N.J.: Prentice Hall. Johnson, T. R., & Case, C. L. (1995). Laboratory experiments in microbiology (Brief ed., 4th ed.). Redwood City, Calif.: Benjamin/Cummings. Karlen, A. (1995). Man and microbes: disease and plagues in history and modern times. New York: Putnam. Karlen, A. (2000). Biography of a germ. New York: Pantheon Books. Koneman, E. W. (2002). The other end of the microscope: the bacteria tell their own story : a fantasy. Washington, D.C.: ASM Press. Krasner, R. I. (2002). The microbial challenge: human-microbe interactions. Washington, D.C.: ASM Press. Kruif, P. H. (1927). Microbe hunters. London: Jonathan Cape. Madigan, M. T., Martinko, J. M., & Parker, J. (2000). Brock biology of microorganisms (9th ed.). Upper Saddle River, NJ: Prentice Hall. Margulis, L., Schwartz, K. V., & Dolan, M. (1994). The illustrated five kingdoms: a guide to the diversity of life on Earth. New York: HarperCollinsCollege. Needham, C. (2000). Intimate strangers: unseen life on earth. Washington, D.C.: ASM Press. Nester, E. W. (1973). Microbiology: molecules, microbes, and man. New York: Holt, Rinehart and Winston. Nester, E. W., & Anderson, D. G. (2005). Microbiology: a human perspective (5th ed.). Boston, Mass.: McGraw-Hill. Pelczar, M. J., & Chan, E. C. (1972). Laboratory exercises in microbiology (3d ed.). New York, etc.: McGraw-Hill Book Co.. Sachs, J. S. (2007). Good germs, bad germs: health and survival in a bacterial world. New York: Hill and Wang. Stanier, R. Y., Doudoroff, M., & Adelberg, E. A. (1970). The microbial world (3d ed.). Englewood Cliffs, N.J.: Prentice-Hall. Tierno, P. M. (2001). The secret life of germs: observations and lessons from a microbe hunter. New York: Pocket Books. Tortora, G. J., Funke, B. R., & Case, C. L. (2005). Microbiology: an introduction (Brief ed.). San Francisco, CA: Benjamins Cummings. Zimmer, C. (2008). Microcosm

see above

Interim Assessments: 

Presentations are the most important interim assessment. Both the presenter and the respondents are expected to participate at high levels of cognitive engagement. This gives a very clear diagnostic of student thinking about microbes, texts, and experimental research.

Other assessments include early drafts of lab report sections, the first entire lab report, and other written assignments including the class notebook. Students are expected to take notes on what they do and learn in every class period. This is largely a laboratory notebook, but also records their thinking on broader issues.

Significant Assignments: 

See above.

Significant Activities or Projects: 

See above.

Sample PBATs: 
How does ultraviolet light affect the survival of pigmented bacteria collected from the classroom environment??
How does the type of hot sauce affect the diameter of the zone of inhibition in Staphylococcus epidermidis
How does calcium propionate affect the colony diameter of Penicillium roqueforti grown on a bread-agar medium?