The aim of this article was to establish whether a biometric fingerprint device can be used to accurately record and improve active class participation of student teachers when attending lectures on the application of differentiated instruction. Quantitative and qualitative approaches were used to collect data. In the quantitative study a student-teacher class (n = 180) of a university in South Africa participated during the second and third semesters of the academic year. The quantitative data consisted of the number of student teachers' active participations recorded using a biometric fingerprint device and data from the second and third semesters were compared. Results were obtained from the calculated number of active participations for which student teachers were rewarded "class bucks" for quality comments. Although class bucks were awarded in both the second and third semesters, the number of student teachers who were actively involved in discussions increased by 18% in the third semester (when biometric fingerprint scanning was implemented). After the completion of their training course, a qualitative approach followed, where participants (n = 36) reflected (through responses to open-ended questions) that they still desired more practice and examples to help them create differentiated activities. It was evident that more activities for practical experiences should be created where student teachers could use various forms of assessment, adjust content, select suitable methods and media, create a suitable learning environment, and identify their learners' learning barriers and learning preferences to create and apply differentiated activities in the classroom.