How About a Magnet and a Paper Clip?

Abstract

Physics education research shows that many introductory physics students have difficulties fully grasping Newton's third law.1 This is exacerbated when we ask for the validity of Newton's third law in areas outside of mechanics, such as electrostatics or magnetostatics. Undoubtedly, there is a difference between hearing about something and actually seeing or feeling it. Students can be told that two forces are equal and opposite but this by no means implies that they are convinced this is indeed the case. Some students respond with the correct answer but still harbor a remnant of doubt that the forces might not be the same.