## A problem-posing approach to the teaching of the Special Theory of Relativity

##### Summary

The Special Theory of Relativity is based on two principles: the relativity principle that says that the laws of physics must be the same in all inertial reference frames and the light postulate that says that the speed of light is constant in all inertial reference frames. From these two postulates we obtained 5 important ideas that we consider are crucial for secondary school students that want to learn the topic, in particular the two relativistic effects: time dilation and length contraction. These ideas are: Movement is not absolute, it is defined by comparing with something else; There are more than one possible reference frames; All of them are equally valid; The speed of light is defined relative to the observer; and All observers measure the same value for the speed of light. Research shows that secondary school learners tend to regard the relativistic effects as a matter of perception and they tend to consider that only one of the reference frames is right. Addressing the first 3 ideas (the ones related to the relativity postulate) might solve this problem. In this work we show how we tried to teach those ideas through a problem posing approach. Furthermore we show that after following the proposed lesson plan students no longer considered one reference frame as the right one and that, to some degree, they do not exhibit concepts of absolute motion.