The goal of this paper is to illustrate different ways that cardsorting activities (or "card stacks") can be implemented in the introductory physics classroom, along with various tips and resources for getting started. My first attempt at developing a card stack came about from simply wanting to try out a fun way to change student…

An exercise which relates particle scattering and the calculation of cross-sections to answer the following question--"Do you get wetter by walking or running through the rain?"--is described. The calculations used to answer the question are provided. (KR)