  Social physics is an active and diverse field in which many scientists with
formal training in physics study a broad class of complex social phenomena.
Social physics investigates societal problems but most often does not count on
the active and conscious participation of the citizens. We here want to support
the idea that citizen science, and more particularly citizen social science,
can contribute to the broad field of social physics. We do so by sharing some
of our own experiences during the last decade. We first describe several human
mobility experiments in urban contexts with the participation of concerned
young students, old women or other different groups of neighbours. We second
share how we have studied community mental health care provision in
collaboration with a civil society organisation and with the intense
involvement of persons with lived experience in mental health. In both cases,
we narrow down the discussion to digital tools being used and the involved
participatory dynamics. In this way, we share key learnings to enhance a
synergistic relationship between social physics and citizen science and with
the aim increase the societal impact of the research on complex social
phenomena.
