Despite the numerous proposals made in the last decade for the use of mobile devices as experimental tools (MDETs), few studies exist providing empirical evidence about their educational effects. This quasi-experimental study investigates the effects of the use of MDETs on motivation and on learning in the physics classes of senior high school of Geneva. A series of activities was created using video analysis to study mechanics during a whole semester. A pilot study and a main study were carried out comparing a treatment group using MDETs for six activities (NPS = 60; NMS = 55) and a control group performing traditional experiments during their physics lessons (NPS = 45; NMS = 56). Lesson plan and learning content of labwork were identical for both groups, and the same teacher taught them. Instruments for assessment of student learning and of affective variables were translated, adapted, and partially newly developed for this study. The results don't show significant variations in the learning achievement, in cognitive load, or affective variables, despite a global pre/post effect size (Cohen d) of about 1 for learning (large), of 0.2 for relation to reality and of 0.3 for interest (small). Moreover, the possibility of the presence of an effect of the treatment on the learning of parallel mathematics is not excluded and should be deeper investigated.