Two Approaches for Teaching Equipment Calibration

Undergraduate crop and soil science laboratories are taught by graduate students at many universities. However, in some instances, due to reductions in funding and/or graduate teaching assistants, this is not always possible. Professors may therefore be required to teach both labs and lectures. This study was conducted at the University of Georgia to compare traditional teacher-directed and self-directed calibration labs. The teacher-directed students had spreader and sprayer calibration explained and demonstrated by a teaching assistant, followed by student participation in calibration exercises. Self-directed students watched a videotape of the calibration process, after which they conducted calibration exercises without direct teacher assistance. Studentʹs perceptions of their ability to calibrate and spreaders were monitored by pre-lab and postlab questionnaires and final exam questions on calibration principles and calculations. The teacher-directed students had significantly higher perceptions of their ability to calibrate both sprayers and spreaders than did the selfdirected students. Although comments from students indicated that teacher directed labs were preferred by a majority of students, there were no differences in performance on calibration questions on the final exam between teaching methods. It appears that self-directed laboratories may be viable options for introductory crop science courses.