Although diffusion is the subject of beginning chemistry classes, there are a variety of experiments, such as the spread of perfume in the classroom, that are often "incorrectly" explained by diffusion alone. To eliminate this common misconception, a recently published method is modified to determine the diffusion constant of hydrogen…

The aroma volatile compounds in tomatoes are strongly linked to taste and flavor. Commercial tomato varieties, however, generally lack flavor. Tomato breeding programs have therefore started to focus on increasing the flavor-enhancing volatiles, which can be more easily altered than the sugar content. Analytical efforts that identify key flavor…

During the pandemic caused by SARS-CoV-2 (COVID-19), a paper analytical device (PAD) was proposed as a tool for remote laboratory classes for undergraduate chemistry to teach calibration curve concepts. For this experiment, students were taught how to prepare a PAD, calibrate standard solutions, construct a calibration curve, and treat data…

The main purpose of this study was to enhance student understanding of the scientific concepts of chemical reaction rate. Forty-four grade 11 students were the target group. The treatment tools were seven learning plans of 5E inquiry incorporated with an analogy learning approach during 15 hours of class time. In each learning plan, the students…

This article explores heterogeneity as fundamental to learning. Inspired by Bakhtin's notion of heteroglossia, a design team consisting of an experienced classroom teacher and 2 researchers investigated how a class of 3rd and 4th graders came to understand disciplinary points of view on heat, heat transfer, and the particulate nature of matter.…

This paper is based upon experiments developed as part of a Directed Research course designed to provide undergraduate biology students experience in the principles and processes of the scientific method used in biological research. The project involved the evaluation of herbal remedies used in many parts of the world in the treatment of diseases…

A classroom exercise for undergraduate and beginning graduate students that takes about one class period is proposed and discussed. It is an easy, interesting exercise that demonstrates important aspects of sampling techniques (sample amount, particle size, and the representativeness of the sample in relation to the bulk material). The exercise…

Presents the procedures, results, and conclusions of a study to compare the effectiveness of the open-ended chemistry laboratory with the traditional laboratory. Different classes of high school students in a college-preparatory chemistry course were exposed to the two laboratory techniques. The achievement tests and the Watson-Glaser Critical…

Discusses revisions in general chemistry laboratory to include group project work. Describes evaluation techniques and sample projects. (MKR)

Data from this study suggest that evaluations of long-term accumulations of students' laboratory analyses should be standard procedure to detect deviations from the accepted true assays. Efforts are recommended to determine the cause of the error and the implications or grading procedures reconsidered. (Author/MA)