Teaching Laboratories Under the Microscope- Part I

The Faculty Perspective

Most college science curricula still have the overall structure of three-days-per-week lecture/4 hr laboratory, at the least for the intermediate-level bread-and-butter courses. Why? What are the goals of those laboratories?

Most laboratory courses are focused on learning how to do particular field-specific techniques and how to gather and analyze particular types of data. The plan is for those laboratory sessions to engage concepts and approaches that complement what is being taught in the “lecture” component of the course. The idea is that students will grasp more deeply those concepts and principles that they do themselves. Learning by doing. As professed on the Stanford University Center for Learning and Teaching website, “students will hopefully reach a deeper understanding of the course material by putting it to work.” Course laboratories are also fertile grounds for developing collaborative working group skills.

While browsing various college websites about course laboratories, I came across some terrific goals for science teaching laboratories:

1. From the University of Virginia: A laboratory experience models how scientific knowledge is constructed and how new knowledge is related to what is already known.

2. From Stanford University’s Center for Learning and Teaching: the lab can be an exciting place for the instructor and the students, as students commit to the processes of investigation, analysis, and reflection.

3. From Vanderbilt University: Laboratory classes provide students with first-hand experience with course concepts and with the opportunity to explore methods used by scientists in their discipline.

With the increasing evidence of the effectiveness of inquiry-based instruction for college science education, many of us have reinvented our labs to include more opportunities for hypothesis-testing, independent experimental design, often in the form of laboratory modules that last multiple weeks. There are many now available online- below are just three sources I’ve consulted.

  • The American Biology Teacher: http://www.bioone.org/doi/abs/10.1525/abt.2012.74.5.6?journalCode=ambt
  • Journal for Undergraduate Neuroscience Education (JUNE):http://www.funjournal.org/
  • CBE: Life Sciences Education: http://www.ncbi.nlm.nih.gov/pmc/journals/421/

What is it about the laboratory experience that helps with learning and understanding important scientific concepts? Is it the actual doing? Is it seeing the process of an experiment unfold?

Let’s take an example. Most science students at some point in their education learn how to measure a chemical enzyme-mediated reaction using a spectrophotometric assay technique. Student carefully measure out the components of the reactiion into tubes called cuvettes. Upon adding the enzyme catalyst, the reaction proceeds and most often one of the products of the reaction is a colored compound because it absorbs a particular wavelength of light. You can determine how the enzyme functions by measuring the amount of product produced over time. To accurately measure the reaction rate requires precise skills like using pipettors, performing reliable and accurate mixing, paying careful attention to time and good notetaking. When I’ve watched student groups doing an experiment like this, they are very focused on the mechanics– on using the pipettors, on mixing the components in the cuvettes without spilling the contents, on writing down numbers as a stopwatch runs up the seconds. Are they thinking about the enzyme’s properties? No! They are trying to be accurate, trying to work their way through the procedure, hoping to finish a good quality data set before the lab period is over (or sooner if possible so they can get to soccer practice or a music lesson). I’ll take up this aspect of laboratory science education in Part II of this series.

I have spent many many hours in the teaching laboratory, guiding students as they design experiments, trouble-shooting countless problems that arise during a lab period, bolstering spirits as students become frustrated, discouraged, anxious. The laboratory experiences, most of them four hours long, leave all of us exhausted. Students shove their lab notebooks into their backpacks and dash away quickly, vowing to look at their work later sometime, but unwilling or incapable of any more science thinking for a while. While a few students actually ask questions about the science behind the laboratory exercise, most seem more concerned with the mechanics of the experience, of whether their data are “good enough” for the lab report they have to write.

Do our teaching labs really teach what we think they teach? What do we want them to learn? Is that what they are learning?

 

Next post: Laboratories from the student perspective

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