In a recent article Fotou and Abrahams (2016 Phys. Educ . 51 044003
[http://dx.doi.org/10.1088/0031-9120/51/4/044003] ) described a study which investigated how
students approach novel situations and whether their reasoning can be understood as theory-like
misconceptions or phenomenological primitives. Two exemplary questions polling students’ concepts of
gravity were presented in their article. Although we find the authors’ motivation and approach
interesting we also raise concerns about one of these problems.