This work examines commonly used particulate-level pictures meant to illustrate gases. These pictures are found throughout textbooks in the middle grades through the college level, as well as in questions frequently used to assess conceptual learning in students. This work uses the kinetic-molecular theory of gases to demonstrate the inaccuracies often present in these figures, which offers the opportunity to address model limitations to students and to develop better pictures. A basis for using these pictures to discuss models and ideas for ways these pictures can be used for inquiry activities based on analysis of scales is also discussed.
Available at: http://works.bepress.com/mark_waner/6/