A single group pre-test, post-test quasi-experimental design was utilized to triangulate quantitative and qualitative data obtained from a questionnaire, field notes, classroom observation, and practicum test scores, to determine changes in the questioning behaviours and practices of 31 prospective teachers involved in a three-week practicum exercise. Paired-samples t-tests were conducted to compare pre-test and post-test scores on participants' level of confidence in asking focussing, prompting, probing, and redirecting questioning. Findings of the study revealed significant differences in participants' pre-test and post-test scores for prompting questions. Based on Cohen's convention for a large effect (d =0.80), the effect size for this analysis (d = 0.82) was found to be large. Analysis of classroom observation and field notes obtained from practicum supervisors also revealed a general improvement in participants' questioning behaviours and patterns after the application of an instructional video.