EVOLUTION IN THE ASSESSMENT CRITERIA OF LAB WORK IN PHYSICS SUBJECTS FOR THE DEGREE OF CHEMISTRY

Laboratory work is essential for learning in the experimental sciences. Not only does it allow students to understand the physics concepts taught in lectures, it also provides students with the knowledge and necessary skills to solve scientific problems.

The First Year Physics Course for the degree in Chemistry consists of 30 hours of laboratory work per semester. Four hours are dedicated to the expression of uncertainty in the results of a measurement, and the rest of the time is dedicated to Mechanics and Thermodynamics Experiments (Physics 1) followed by Fluids, Circuit and Magnetic Field Experiments (Physics 2).

In this work we suggest an alternative method for the assessment of laboratory work in the subjects of Physics 1 and Physics 2 for the degree in Chemistry.

To this end, we compare the results obtained through this alternative method, used in the latter two years, with the traditional system of evaluation using laboratory notebooks.

At the beginning of the Degree, a lab notebook was used in the assessment of students' lab work. To make this notebook, students had to do a report on each experiment. Each lab report was organized in a similar manner, that is, it was divided into labelled sections where each section had a specific purpose. The account of every experiment began with a title followed by a brief theoretical introduction. Next, there was an experimental section where students collected the experimental data and noted every step carried out during the process. Students finished with a section discussing the results and conclusions.

Students could get up to 1.5 points in this activity but the marks obtained in the lab notebooks were not as good as we expected. The average value was 0.9 points. We observed that students had problems communicating in an orderly way what occurred in an experiment or observation, and they also had problems discussing clearly the results on the basis of experimental data.

These findings made us consider changing the method of assessment in laboratory work, with an aim to improving the final marks in this activity.

We decided to elaborate a lab worksheet for each experiment that allowed students to order their ideas, clarify concepts more easily, and grasp the purpose of the lab practical. In addition, we focused part of this worksheet on the treatment of experimental data and indicated the way in which the result of the analysis should be expressed. Students had two rounds of corrections, a first one where the teacher marked and assessed the mistakes, and a second one where students could correct mistakes and improve their marks.

The results obtained with this new method were better than the traditional one and we obtained higher student motivation and involvement, greatly improving the learning process.