In this paper we present the results derived from a project aimed to study the "learning gains" obtained by undergrad engineering students that used two mobile learning resources (in video format). We conducted our study over a 6-year time interval applying "pre-test" and "post-test" instruments to both experimental groups (which used the mobile resources) and control groups (which did not). Our sample consisted of N = 793 students and we found that the experimental group obtained learning gains about 26% higher than those of the control group. We found this difference to be meaningful, with "p"-values around 0.022. Perception questionnaires applied to the control groups showed that most of the students consider that the use of mobile resources improved their concept-comprehension and helped them to develop their problem-solving skills. [For the complete proceedings, see ED601100.]