  Covariational reasoning -- how one thinks about the way changes in one
quantity affect another quantity -- is essential to calculus and physics
instruction alike. As physics is often centered on understanding and predicting
changes in quantities, it is an excellent discipline to develop covariational
reasoning. However, while significant work has been done on covariational
reasoning in mathematics education research, it is only beginning to be studied
in physics contexts. This work presents preliminary results from an
investigation into expert physicists' covariational reasoning in a replication
study of Hobson and Moore's 2017 investigation of covariational reasoning modes
in mathematics graduate students. Additionally, we expand on this work to
include results from a study that uses slightly more complex physics-context
questions. Two behavioral modes were identified across contexts that appear
distinct from those articulated in the Hobson and Moore study: the use of
compiled relationships and neighborhood analysis.
