Academic journal article Journal of College Science Teaching

A Case Study for Teaching Quantitative Biochemical Buffer Problems Using Group Work and "Khan Style" Videos

Academic journal article Journal of College Science Teaching

A Case Study for Teaching Quantitative Biochemical Buffer Problems Using Group Work and "Khan Style" Videos

Article excerpt

For well-trained specialists using expensive hardware, the possibilities for video instruction have been with us for many decades. Very recently, there has arisen a combination of inexpensive hardware (a ~$60.00 drawing tablet), free software, and free universal access to video storage and retrieval sites on the internet. These developments have now put video production into the hands of any interested party with minimal training (Gannod, Burge, & Helmick, 2007). Salman Khan (director of the Khan Academy website) has created hundreds of science instructional videos that share certain characteristics. They are short (~15 minutes or less) and consist of a black background with extensive use of color for formulas and drawings. The teacher's voice is synchronized to the activity appearing on the computer screen. At no time does the teacher's face or hands appear in the video. The end result is somewhat mesmerizing (a Kahn video example on the topic of buffers can be found at

As university biochemistry professors, we were particularly interested in scientific videos that involve the presentation of complex quantitative topics (Eick & King, 2012). Buffers are one example of a problematic quantitative topic, and experience has taught us that this subject area is particularly difficult for our students to master. Other faculty members agree (Orgill & Sutherland, 2008). Our working hypothesis in this study was that video lectures, assigned as homework, could replace live classroom lectures in the presentation of buffer theory and problem solving (He, Swenson, & Lent, 2012; Prober & Health, 2012), particularly when combined with a collaborative learning environment (Case, Stevens, & Cooper, 2007; Johnson & Johnson, 1974). The preceding assertions need some "case study" documentation if they are to be adopted on a wide scale by understandably skeptical, and traditionally cautious, academics (Bell, 2012).

"Inversion of the classroom" has some inherently appealing characteristics. We have noted that students have less and less appetite for individually working difficult problems on homework assignments, and their response to a long "live lecture" is to tune it out (Deslauriers, Schelew, & Wieman, 2011). We have also noted that lecturing has a long, well-documented (and frequently ignored) history of failure as a problem-teaching tool (Powell, 2003). Group problem solving in the classroom means that both the group and the teacher are available to help but has been criticized as too time-consuming, leaving little time for lecture. Our video lecture homework can be viewed from anywhere and at any time students prefer--hopefully when they feel attentive and focused. The videos can be repeatedly rewound and reviewed. They do not consume class time, creating a window for group problem-solving sessions during class.

Khan videos are less available for upper division science classes, and we became interested in converting a junior-level biochemistry survey class (enrolling mostly biology majors) to the inverted classroom" format. In the past, the topic of buffers often seemed to produce test anxiety (and failure) in our student population. Chemistry II buffer lectures (>90%) were the most common type of preparation for our students, and very few students had taken analytical chemistry prior to taking biochemistry.


A number of methods were used. First, over a 3-week period, students watched seven buffer videos by receiving e-mail links to YouTube videos with a specific class day set for completion. Second, on the due date and without further explanation, they arrived in class and were asked to go to the board in groups of four or five and work a buffer problem to a final solution; collaborative problem solving is a very important part of our method (Klionsky, 2001; Paulson, 1999). Three different buffer problems were given to four to five students randomly assigned to six groups so that each problem was worked by two groups. …

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