There is genuine ignorance on inertial frames of reference, and an understanding of how we achieve a limited inertia frame with and air table or billiard table. I genuinely despair when I see the basic conventions of electric field lines cast aside. If you make the point that it makes advanced teaching that little bit more inaccessible, you can imagine the joy with which people affirm that it doesn't matter. MP4 recording     MP3 recording -- -- Your browser does not support the audio element.