Putting the Laboratory at the Center of Teaching Chemistry

Putting the Laboratory at the Center of Teaching Chemistry

A. M. R. P. Bopegedera

Journal of Chemical Education 2011 88 (4), 443-448

DOI: 10.1021/ed100045z

ABSTRACT: http://pubs.acs.org/doi/abs/10.1021/ed100045z

In this article, the author, a Chemistry professor at Evergreen State College in Washington, gives a description of non-traditional lab activities that represent a “holistic” approach (Lab-Centered Approach or LCA) to connect theory learned in lecture to practice done in lab.  The lab activities described by the author are described below:

·         Lab write-ups are used (I am assuming handouts of labs) instead of published labs.  The author did not give a description of whether these labs were created in-house.  The students are required to record everything in a lab notebook (something we already do at LPC) as opposed to the practice in many other colleges of using lab report forms from the publisher.  Students are asked to answer pre-lab questions as a requirement for doing the lab.  Students are asked to submit the lab report the next day (students have a week at LPC). The discussion section consists of questions that students need to answer to help them think through the lab (done in some labs at LPC).  Overall, this protocol sounds no different from what we already do at LPC.

·         Students are given a lab map to familiarize themselves with parts of the lab, something we do at LPC as well.

·         Students work with lab partners for every lab.  The author notes that when students have to learn how to use a new instrument, they work with each other and their mastery is closely monitored by lab staff (at LPC, the students don’t work in pairs for every lab.  I, myself, go around to make sure students know how to use our Lab-Pro and the different sensors we use for it.  Not very easy to do with the larger AA instrument. Lab staff do not normally have time to hang around in the class during the lab.)

·         The author also made special mention of students cleaning up after themselves, something required and routine in most of the labs  I have taught so I am not sure why this got special mention.

·         Grading is more process-oriented rather than results-oriented.  They are graded on the basis of their work, their technical writing skills, and their suggestions for improvement.

·         Lab problems are incorporated into their workshop (a form of problem-solving discussion session), quizzes, and exams.  (I do a little bit of this already but I plan to do more of it to give students more incentive in producing good, thorough reports.)

·         He also wrote a brief description of how he conducts his lecture which he describes as being very interactive.  The students also attend a 90 minute workshop on problem solving in which groups of students work together on problems and the instructor rotates through them, spending more time with struggling students.

·         Students in the first year chemistry class take labs where the activities represent a progression from simple verification experiments, to guided-inquiry activities, and then to open-ended inquiries.  The author mentioned that in the first quarter, students only do 4 labs as it takes time to cycle through all the classes in 10 weeks (I am not sure what he meant by this).

·         The author did not give a description of what the guided inquiry labs are but they were included in the supporting document.  In this step, he did mention that students have to work with more analysis data and he seems to imply that there is more one-to-one interaction needed in this case because of the nature of the activities.

·         In their last quarter, spring, groups of 3-4 students carry out an open-inquiry project where they have to come up with their own question and hypothesis, do some background research, design their experiment, order their chemicals, and carry out the project to fruition.  They are then presented during a science carnival event at the College.  The author provides a timeline of expected outcomes for the open-inquiry project and also some of the interesting projects that have come out of the class.

It is hard for me to imagine, although it sounds ideal, being able to have our 1A and 1B students carry out guided-inquiry and an open-inquiry projects.  We would have to eliminate a large portion of our lab curriculum and replace it with these projects. I am not sure how much lab support it might take to carry out an endeavor like this.  Furthermore, students don’t always end up with the same instructor for the second semester.

The author provided some qualitative assessments of the effectiveness of this approach in the form of some selected students comments all of which were positive. He presented some quantitative data on ACS exam results but did not elaborate as to whether they pre- and post-LCA or if they are results from the two years of using this approach. In the notes section, he did add this, “Based on information from the Registration and Records office of TESC, 76% of the students continued their studies in the sciences in subsequent years. This number excludes students who graduated or left TESC at the end of the academic year of the LCA”.

The last section was devoted to a description of incorporating a lab practical, something I have always wanted to do for the General Chemistry course.  However, this takes time not just away from students conducting more labs (It is always a difficult decision to figure out what lab to eliminate to make room) but also this is very work-intensive from the lab support end.  He shares the same reasons I have for adding a lab practical to the curriculum (which I have done for the 30A lab).  Listed verbatim, they are: “(i) emphasizes that what is learned in the laboratory is as important as what is learned in lecture; (ii) holds students responsible for learning lab techniques; (iii) provides students an opportunity to synthesize data from multiple experiments to reach a single conclusion; (iv) tests students' ability to work independently and resourcefully in the laboratory; (v) rewards students for good record keeping (lab notebook was the only resource allowed during the lab practical); (vi) tests students' ability to write a formal lab report without help; and (vii) helps students gain confidence in the laboratory before starting independent lab projects.”  The lab 3-hour lab practical required each student to determine the identity of the metal nitrate using a variety of techniques: complexometric titration, Beers- Law measurements, etc.  It sounds really interesting and I am intrigued.  More importantly, he discovered areas where students were weak and could have used more help, graphing, precision and accuracy, qualitative versus quantitative data, etc.