Abstract:

The effectiveness of an instructional video of QuEChERS methodology as a flipped teaching tool in the “Food Analysis Laboratory” of the Masters’ Degree in Experimental Techniques in Chemistry at the University of Valencia is examined in this work. For this purpose, a laboratory experiment entitled “Evaluation of pesticide residues in fruits by gas chromatography coupled with mass spectrometry” was recorded with the assistance of visual media professionals. The recording process began after setting the required equipment or glassware, followed by the filming of all the experimental steps that the student will do in the lab, which include procedures’ description (performing), use of instrumentation and waste disposal instructions. Once video was recorded, it was edited, audio was recorded and both video and audio were merged. Finally, the finished video was published online both in the University of Valencia repository and in YouTube to assure a reliable access to all students. Next, before coming to the lab, students were asked to watch the video at home, since it would help students to be better prepared for the laboratory, also increasing their understanding of the theories and concepts presented in the video. In addition, and in order to increase video visualization, an online prelab test using the Socrative tool was passed to the students once in the lab, and before the beginning of the experiment. The result of this test accounted a 4% of the laboratory mark. Finally, at the end of the experiment, students completed a postlab satisfaction survey, in which they evaluate both the effectiveness of the video regarding lab preparation and how satisfied they are about the application of the video as a prelaboratory requisite. Most of the students reported that the video helped them to feel better prepared to conduct the experiment showing also a high satisfaction degree in the implementation of the video to prepare the laboratory experiment.

Keywords:

QuEChERS methodology, instructional laboratory video, flipped prelaboratory teaching, postlab satisfaction survey.