We describe the design and implementation of a teaching-learning sequence that was started before the lockdown and was then transformed for distance teaching. A backward design approach was adopted in order to identify clear learning outcomes. The activities were outlined according to an inquiry-based learning paradigm, referring to research-based models. We discuss how these elements were relevant when redesigning the activities for distance teaching. In particular, we describe how we modified an 'application experiment' (measuring the thickness of a human hair) using a video-based activity, highlighting how this activity was designed in order to meet the original goals and outcomes. The results of the teacher's assessment and the students' self-evaluation suggest that the approach was meaningful and effective, and that the experience can provide useful hints also for teaching under regular conditions.