Sorry to start yet another thread on the basics of magnetism, but I'm missing something... Glancing through an introductory college physics textbook, the three chapters on magnetism are missing something ...and it is the one thing that every normal person thinks of when they here the word magnet... In this text, there don't seem to be any equations or discussion involving the the attractive or repelling force between two magnets, or between magnet and metal. It seems like that should be a starting point for discussion in introductory physics, since those are the properties of magnets most people are accustomed to. In the text, I see the effects magnetic fields have on currents, and the way current loops have a magnetic moment, and what kind of torque will be enacted on them, and the electromotive force resulting from a changing magnetic field, or changing current, magnetic field strength due to various configurations of wire, etc... For one, how do you measure a magnetic field? The units are Tesla, and the direction can be determined by a compass, but how do you measure the strength? Is the magnetic attraction force a side-effect of the two magnets aligning themselves, and the changing currents inside the materials, or is it a completely independent phenomenon?