Iteration

Now that I've introduced the basics of a CURE, I'll detail each of the tenets in its own post. However, many are inter-related, so it was difficult to choose which order to introduce the following posts. Here goes!

One of the tenets of a CURE is Iteration.

The Concept

Iteration sets a CURE apart from other types of course-based laboratories in the same way as another tenet: Discovery. While Discovery awaits its turn in the blog queue, I'll introduce it here briefly. Discovery means that students engage in research to which the answer is not known in advance. Some call this "authentic" research, because it forces students to grapple with an undoubtedly critical reality in science: practicing scientists have to be thorough and precise to design and execute an experiment that will (hopefully) definitively address a hypothesis.

For the instructor, and for the student, Discovery can be uncomfortable. Students grapple with the uncertainty that there is no "correct answer" (although they'll still ask you repeatedly to review their lab notebook to make sure their "data look right.") Instructors have the advance task of designing a class schedule that is flexible enough to accommodate the reality that experiments won't always work properly the first time.

In my intro chemistry labs, each experiment had a correct answer, and if we didn't arrive at the correct answer, we didn't earn full credit on that assignment. But if we didn't grasp the intricacies of that experiment, that was often OK, because the next week we were doing something totally different.

However, in many CUREs, as in all scientific research, if something doesn't work properly the first time, one either has to troubleshoot (which usually involves making a change to the protocol and repeating it) or identify a different method to perform the same sort of analysis. Because each project will encounter different hurdles, it is an important challenge for the instructor to design the schedule of a CURE to accommodate the fact that the experiments students will design will need some time for revision and repetition. Iteration.

Example Course

I teach in a semester-system school, so while I have much more time than those on the quarter system, I still struggled to fit what I thought would be enough "flexible time" into the class schedule. That struggle is why I'm sharing with you now the second iteration of my class schedule. The first iteration seemed to work pretty well last semester, and now I've done what any good scientist would do: collected data (feedback and observations) and revised for the coming term.

Before getting into the details, my own philosophy about lab course design for a CURE (and for most courses, for that matter) is to dispense with "breadth" and "content coverage" in exchange for "depth" in fewer topics. My perspective is that this leads to longer-lasting retention of the important scientific concepts I emphasize.

With that in mind, let's look at my course in detail. I supervise non-tenure-track faculty (lecturers) who teach an undergraduate, upper-division lab course in Genetics and Cell Biology that is required for all biology majors. The course meets once weekly in one three-hour block for a semester.

Enrollment tends to be about 18 students per section, and because of equipment (and space) limitations, we tend to have students work in six groups of three in this lab course.

Later (in another post), I'll delve into more detail about guidelines for how to pick a research area or topic for a CURE. Suffice it now to note that it makes a lot of sense (for so many reasons…) for the instructor to pick a research topic that aligns with their own research agenda/expertise. In my case, I wanted to develop a CURE related to worm genetics (specifically, in the species I study, Caenorhabditis briggsae).

Historically, this lab course introduced students to what our molecular/cell biology/genetics faculty felt were critical skills, such as microscopy (the main cell biology component) and Mendelian genetics and molecular genetics (e.g. micropipetting, PCR, and agarose gel electrophoresis). So, my plan for this course, redesigned as a CURE, was to instruct students on these techniques, as well as to the biology of C. briggsae, and then to ask them to design and execute research projects using at least some (but not necessarily all!) of these skills to study C. briggsae biology.

This presented the first question as I thought about the course schedule: how would I structure the introduction of students to the fundamentals of working with worms (e.g. life history and development, anatomy, husbandry, and setting crosses and so - necessarily - manipulating 1 mm-sized organisms) and of the techniques they might need to use in experiments they would design (e.g. measuring worm lifespan and fecundity, PCR and gel electrophoresis, microscopy).

CURE Schedule and Major Assignments

This coming semester, we have fifteen class meetings. The first half of the semester is dedicated to learning about the experimental species and practicing those core cell and genetics techniques (microscopy and PCR).

Importantly, in my experience, we've moved away from instructor "lecturing" about worm anatomy, how to set crosses, the genetic diversity among different populations, and so on. I found in past semesters that, when students presented their research at the end of the term, they couldn't explain WHY they had performed the experiment that we had led them to conduct. I reasoned (which is perhaps true) that it was our fault: we hadn't given students the opportunity and incentive to fully understand the intellectual basis and motivation for "going through the motions" in their lab exercises every week.

So, how did the lab experience evolve? Now, each week during the first four weeks, we introduce and have students practice a new technique: 1) microscopy and viewing worms, 2) pipetting and worm manipulation (picking up individual worms and moving them from one Petri dish to another, 3) pipetting (again, because students really need the iterative practice!) and then setting PCR, and 4) agarose gel electrophoresis. And, because PCR does not always work well the first time, we built in some time for Iteration: weeks 5 and 6 also have time set aside for each group to repeat the PCR and then gel.

Now, none of these exercises really takes a full three hours, and there are already some gaps of time (because once you set up the week 3 PCR reaction, it takes four hours for that reaction to complete…). So, perhaps oddly for a lab course, the rest of the in-lab time in weeks 3–4 involve small group presentations by students on worm biology and then on worm genetics research papers. Each group is assigned a different worm biology topic (and the next week a different research paper) and presents it to the class. The point of having students do this instead of the instructors is at least four-fold (please comment if you have additional thoughts about benefits of this approach!)

• This provides opportunities for students to practice oral presentations with their group members and to become more comfortable talking in front of the class (particularly important because they give an oral presentation of their research project at the end of the semester)
• Students who are giving the presentations learn their material better than they do when listening to the instructor tell them the same information
• Likewise, we've observed that students listening to peer presentations tend to be more engaged and alert (and willing to ask questions) than when an instructor gives the presentation
• Students practice reading both lay and review literature as well as primary research literature. Not only is this a good skill for undergraduate STEM students to develop, but we've also observed that this really helps students understand the intellectual background behind the published research projects they present (and later helps them understand and rationalize the research projects they will develop that are, at least in part, based on this literature review)

We also provided rubrics for the presentations and pointed groups directly to specific topics and literature to read, and specific points to consider making in their presentations. For example, in this worm species, there are two sexes: male and hermaphrodite. They can be visually distinguished, and it is important to do so if setting a cross. So, for the group that presents on worm anatomy, we point them toward published literature that contains useful diagrams and we suggest that the students describe how to distinguish the sexes under the microscope.

Back to the overall course schedule. After week 4, the introductory student presentations are complete, and (as mentioned above) weeks 5 and 6 are used by groups to perform any repetition of the fundamental lab techniques that might not have worked well the first time around (Iteration). In this CURE, even if PCR and gel electrophoresis worked well the first time, we still have students continue to practice isolating and moving worms, for example. During these same two weeks, students are also developing a draft hypothesis and experimental design, which they present (very briefly) to the class, and discuss with other classmates to get any feedback. Over the week, the instructor then reads and provides suggested changes to the hypothesis and to the experimental design. For the hypothesis, we stress that it must be founded on published research (i.e. they need to cite research that supports the intellectual merit of the hypothesis) and also related to the course topic (Genetics and Cell Biology). For the experimental design, we provide advice on what is feasible to accomplish given equipment and supplies (cost) as well as the time available for experimentation.

Then, the next week (6), the students make any revisions to the written design during class and turn in a "final" version (with the understanding that experiments are almost always in a constant state of change…). This version, most importantly to us, is accompanied by a list of anticipated materials each group will need. More on that aspect of CURE coordination to come in a future post!

The groups then have the next six weeks to conduct their experiments. There is no lab agenda, other than every student must show up and help their group! This gives most groups enough time for Iteration! If an experiment doesn't work the first (or second) time, they have the opportunity to demonstrate their perseverance as scientists, making changes to protocols and trying again.

Week 13 is dedicated to data analysis and preparation of their written report and their oral presentation, although the instructor consistently helps students analyze and interpret their experimental results during the entire research process (e.g. conducting and interpreting statistical tests, creating visual representations of their data, like graphs).

Finally, each group presents an oral report of their project to the class in Week 14. And that's the end (other than a lab practical final exam in Week 15). Of course, there are many more details to share about the end of the term, and I'll address them in a later post on another CURE tenet: students should be Assessed like scientists.

Summary

Ideally, the course schedule for a CURE will balance keeping students engaged and active (e.g. having meaningful activities each class meeting) and the flexibility for different students or groups to move forward at different paces. In a perfect world, the schedule will help students feel that there is no pressure for an experiment to work as expected the first time. It is important for scientists to realize that Iteration is a normal part of the process! Devising this type of schedule is no easy task. The approach I've described above, in which the first third of the course is dedicated to learning techniques and background information, with the rest of the course being relatively adaptable depending on progress, has worked well for me, and I hope this approach helps you consider how to schedule your CURE course!

If you find yourself struggling to eject "content" from your course to allow "unscheduled" time for Iteration, then I leave you with this thought. I have had numerous students approach me at the end of this CURE course design and offer various positive reflections on their experiences. In general, they tend to follow the topics of "I wish I had been able to take a class like this earlier," and "I finally feel like I understand the scientific method and how real research projects work." In other words, with your support in a CURE, students can develop important scientific skills (but maybe not quite all of the discipline-specific content you would prefer…) like information literacy, perseverance, troubleshooting and critical thinking, among others.

Content exposure can be important, especially if your course is a prerequisite for another, but there are still ways to facilitate student exploration of that content in a CURE.