Selection and evaluation of experiments in instrumental analysis for schools with limited instrumental resources utilizing the inquiry oriented approach.

Abstract

The purpose of this study was to develop and evaluate a selection of experiments in instrumental analysis for schools with limited instrumental resources. The primary intent behind the selection of experiments was to develop them in such a manner that students would have the opportunity to acquire physical skills in working with laboratory instrumentation, study the scientific method, develop critical thinking, and initiate investigation in the chemical laboratory. Six experiments for ultraviolet/visible and gas chromatography were selected for field-testing and evaluation. The instrument chosen for the content analysis was the Laboratory Structure and Task Analysis (LAI) by Tamir, Lunetta, Novick, and Fuhrman. The LAI was designed as a tool to measure inquiry oriented laboratory curricula. Qualitative open-ended questions designed by the investigator were also included as part of the evaluation.

The investigator initially performed a content analysis of the experiments using the LAI. The field-testing by students was accomplished at Lee College, Cleveland, Tennessee during the spring semester of 1996, utilizing a laboratory which consisted of junior and senior chemistry majors. In addition, professors from several large public institutions and smaller private schools in Tennessee, Kentucky, and Texas were asked to evaluate the experiments.

Results from the evaluation by the professors and the field-testing by the students indicated an average inter-coder agreement of 86% for professors and 90% for students signifying an acceptable consistency for the coders' assessment. Data from a t-test indicated the student and professor results were not significantly different from the investigator's results thus confirming the conclusions of the investigator's original content analysis of the selection of experiments. Another part of the evaluation was a test of preference to determine if there would be a significant difference between types (traditional, combination, or investigative) chosen by students and professors. The problem statement was written in the null form and rejected in all cases. Therefore, the conclusion was established that both students and professors preferred the combination type experiment with 92% of the professors and 70% of the students selecting the combination experiment. The selection of experiments is included in Appendix IV of the dissertation.