The problem addressed by this study is that first-year college chemistry students learn little of the conceptual material associated with chemistry experiments they perform. The thesis of this research is that the construction of prelab and postlab concept maps help students understand the concepts involved in the experiments they perform. The study was conducted using 32 non-science majors enrolled in a first-year chemistry course. The experimental group constructed prelab and postlab concept maps, while the control group wrote essays explaining the conceptual chemistry of the four experiments used in this study. Both groups took 25-item achievement tests 1 week after each experiment. Prelab and postlab concept maps were scored and evaluated for significant differences. Five students were interviewed to investigate their perceptions regarding the usefulness of concept maps in chemistry laboratories. No significant differences were found between treatment groups with respect to students' conceptual understanding as determined by the multiple choice achievement tests. Students responded very positively toward the use of concepts maps in the laboratory. They felt strongly that constructing prelab and postlab concept maps helped them understand the conceptual chemistry of the experiments.

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This article describes a two-week experiment for introductory chemistry students, where they analyze the lead content of paint chip samples using atomic absorption spectrophotometry (AAS). It involves the preparation of standard lead solutions, preparation and analysis of paint chip samples (including a standard reference lead sample) using AAS, construction of calibration lines, weight % lead calculations, and proper disposal of all waste solutions. Average relative percent errors for students' results consistently decrease between weeks one and two as students become more proficient at the preparation of standard lead and paint chip sample solutions.

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