Abstracts of other recent presentations

Contact Keith Anliker (anliker@chem.iupui.edu) for additional information

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More than a collection of discrete experiments: Changing our approach to introductory chemistry labs

Keith S. Anliker and Cynthia G. Kelley

Abstract of a talk presented at the 18th BCCE in Ames, Iowa on July 19, 2004.

Many lab manuals used in introductory chemistry courses consist of a collection of one-period experiments where each experiment covers a few basic concepts or techniques. Once the period ends, the experiment is over and there is little likelihood of any continuing discussion—even if students have lingering questions about the concepts involved in the experiment. Not surprisingly, this approach can be very frustrating for students at the introductory level.

In an attempt to improve the lab experience for our introductory students, we created a series of two to four day projects where the work each week is connected to the work in previous and future weeks. Our goal is to bring students along on the important concepts—always allowing them another opportunity to clarify their understanding as we move forward. One key aspect of this approach is a guided discussion at the start of the next lab period that focuses students on the work from the previous week and connects it to the next part of the experiment. The questions are conceptually challenging and are intended to make the students stretch their understanding of the current project. Another key aspect of this approach is a final report that requires students to integrate concepts from each week’s work and to demonstrate their level of understanding once the project is finished.

Examples of the experiments, discussion questions, final report questions and the way we implement this approach to lab will be described.

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Second chance exams: Philosophy, logistics and results

Keith S. Anliker

Abstract of a talk presented at the Central Regional Meeting of the American Chemical Society on June 3, 2004.

From my course syllabus: “For exams 1 and 2, an opportunity will be offered that will allow you to improve your score by taking a similar exam approximately one week after the exam is first taken. If your score on the ‘second chance exam’ (SCE) is better than your score on the original exam, 80% of this difference will be added to your original score. This opportunity will not exist on exam 3 or the comprehensive final.”

A primary motivation for SCE implementation was giving students incentive to restudy and master material from early in the term—a key to later success. Other motivations were to improve overall student performance and to lower the proportion of students receiving grades of D, F or W.

The implementation has been successful. As expected, students are very appreciative of this approach. The impact on certain individuals has been remarkable, with best-case improvements on an exam as high as 40 percentage points (from 60/160 to 124/160). Average improvements are in the range of 5 to 15 percentage points—still enough to impact students’ grades substantially. These positive results have occurred across all grade ranges, yet we have not seen a decline in performance on our comprehensive final exam when we look at scores received by students earning course grades of A, B, or C during terms prior to and since adding SCEs.

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The oscillating platinum wire demonstration

Keith S. Anliker

Abstract of a talk presented at the Central Regional Meeting of the American Chemical Society on June 3, 2004.

The oxidation of methanol to formaldehyde in the presence of a hot platinum wire is a great demonstration because it illustrates a number of chemical principles. This demonstration has been reported at least three times in the “Tested Demonstrations” column in the Journal of Chemical Education and appears in books of chemical demonstrations in various forms. Even with numerous references to consult, getting the demonstration to work is not an easy task. The focus of this talk will be on a simple setup that works consistently and is suitable for use in large or small classroom settings. The chemistry involved will also be discussed along with how the principles illustrated by this reaction can be brought into an introductory chemistry course.