This talk is aimed at postdocs in symplectic and contact topology who may not have a sense of the physics roots of their subject,
and would like this sense, with a bit of physical intuition. I will discuss Noether's theorem for Lagrangians relating symmetries, its
symplectic re-incarnation, focussing on the Kepler problem and the equations for a particle in a magnetic field. I hope to run this more as a question-and-answer session, but will have enough prepared for a full-on lecture.