Dr. Jonathan Y. answered 07/02/13
Chemistry with PhD, Science Tutor, STEM, Test Prep, ESL, ELL
Rotational Symmetry is part of Group Theory. For HS STEM subjects, rotational symmetry is often introduced using 2D figures or 3D objects. I believe ALL, I mean all, children can understand and eventually master rotational symmetry by practicing with figures and objects with n-fold rotational symmetry. One important point is to pin point the rotation axis.
Games, video, observations inside and outside classrooms, schools and homes and asking student to make a list of objects/figures having rotational symmetry, all helps student to understand and master it. Also the formation of symmetric pattern from individual objects or pieces, and many other ways too, can be used to help students understand and master rotational symmetry.
Why stop there! There are other type of symmetry too, help students see them!!
Once students get their hands on experience and with minimal instruction from teacher, students will get it and own it for life. It is like riding a bike or swim, once you learn it, you know it for life.
In chemistry, one may bring forth the wonder of molecules and crystals with all sort of symmetry as a lot of highschoolers trend to enjoy seeing those pretty pictures and objects.