Abstract:

Laboratory activities have been included in most university chemistry programs since the end of the nineteenth century. Laboratory work is considered by educators to be highly beneficial, giving students the opportunity to take contact with chemical systems and data collection useful in understanding theoretical concepts. The experimental part of a chemistry module is an interesting implement for engaging students in investigations and discoveries.

Traditionally, students carry out experiments following a recipe-style fashion and they submit their reports on these experiments for grading. The assessment is hence limited to evaluate lab notebooks and direct observation in the laboratory. Students can, sometimes, submit reports that are copy of other students’ ones. Additionally, written reports provide limited information related to students’ performance.

However, because of the potential of experimental lessons mentioned above, an appropriate assessment of laboratory work should be designed, considering the conceptual, procedural and skills development learning that take place. A number of articles and reviews have been published in the literature regarding laboratory work assessment. Written tests have been used also as an evaluation strategy. This methodology, does not consider students’ experimental execution, but the design of appropriate questions may catch their capability to reflect about the laboratory work and its relationship with theoretical concepts. The students’ performance and their decision making skills may be assessed by practical examination. Nevertheless, temporal and logistic limitations are the main drawback of this approach. The continuous assessment is a dynamic process that allows covering a variety of tasks and skills that comprise a total program of science-based practical work [2].

In view of the importance that the assessment process have in the proper development of the laboratory practices teaching, we explain in this communication our three years of experience in the teaching-learning process of the Chemistry of Materials laboratory module, included in the Civil Engineering degree program at the University of Extremadura.

The first year, assessment relied on post experiment written questionnaires, solved in a collaborative manner with the aid of the educator. A lack of interest of students in the laboratory work was perceived. Then, the following year, with the aim of overcoming previous deficiencies, we added a test at the end of the term in the grading process. A high failure rate was obtained, and as a consequence the third year we designed a strategy based in a questionnaire previous to the practical work, a questionnaire right after de practice was done and a rubric to evaluate students’ skills during the lab session. This methodology led to better results and students felt well scored. However, we feel that some students were over-graded and further action to enhance the assessment method is to be taken.

References:
[1] Hofstein, A. Chemistry Education: Research and Practice 2004, 5, 247-264.
[2] Gron, L. U.; Bradley, S. B.; McKenzie, J. R.; Shinn, S. E.; Warfield Teague, M. J. Chem. Educ. 2013, 90, 694-699.

Keywords:

Laboratory work, chemistry, assessment methodology, engineering.