Learning is a multifaceted process with cognitive, affective and social dimensions. Therefore, no single instrument can measure learning processes reliably, but a multimodal approach is needed. In the lookout for new, relevant data modalities to triangulate with traditional sources like self-reports, autonomic physiological measures (e.g. electrodermal activity, heart rate) emerge as convenient candidates, since increasingly available wearable sensors provide unobtrusive, continuous measures suitable for studies in ecologically valid settings outside the lab. Electrodermal activity (EDA) is one of the most widely used (and some add abused) responses in psychophysiological research. The electrodermal system is purely innervated by the Sympathetic Nervous System (SNS), responsible for the so called fight or flight response. Cognitive, affective and motor processes activate the SNS, and such sympathetic arousal is measurable through EDA, a highly sensitive response. Not without pitfalls to be avoided, EDA affords a “new” dimension to capture the invisible expressiveness of the body in a learning process. In this talk, PhD student Héctor J. Pijeira Díaz presents experiences, methodological approaches, and findings from working with this kind of data measured from 12 students throughout an entire high-school Physics course.