 Although electromagnetism has been responsible for virtually every human experience and phenomena that we see, that wasn't obvious for a very long time and there are simple reasons for that. The first is that all those different experiences that we have and different phenomena look very different and they also don't look anything obviously like electricity or magnetism. What is now obvious electrical phenomena like lightning, electric eels, St. Elmo's fire or magnetic phenomena like magnets and compasses and so forth, they're not obviously related either. All those things look quite different if you don't understand electricity and magnetism. Indeed the history of experiments and realizations about electrical and magnetic phenomena throughout the last few thousand years is a very long and dense list. People have been conducting experiments all the way from the ancient Greeks who realized that they could make static electricity by rubbing amber on things all the way through to probably the late 1700s and 1800s where people started to really quantify electrical and magnetic phenomena and even more importantly people started trying to use electric phenomena. In the late 18th century people were attempting to make devices to communicate long distances by using static electricity and wires and in the turn of the 19th century Alessandro Volta constructed the first device to make a nice large electric current by a chemical reaction. So he made an electric battery that people could use for their experiments and for their devices and the ability to make electrical circuits then let people make a raft of discoveries in both electricity and magnetism and indeed in the first half of the 1800s people discovered that electricity and magnetism were connected when they started passing current through wires and noticing that they could move compass needles and so once they discover that they could make forces of electricity suddenly this opened the door for the revolution in technology that is our almost ubiquitous use of electricity but all these lovely new electric circuits much like all the previously discovered electrical phenomena all share one thing in common and that is that they're actually all really complicated examples of electromagnetic theory and the reason for that is electromagnetism fundamentally is all about charges and how they affect each other and in something like an electric circuit or a battery or a cloud or a fish or a compass there are so many charges in such complicated arrangements in any of these objects there are enormous numbers of positive and negative charges all really near each other and virtually canceling each other out and it's just the tiny differences the little movements of those charges that lead to these interesting effects so it took nearly a hundred years and many people working on it to really understand the fundamentals of electromagnetism to understand what charges are and what they do to each other and one of the things we have to discuss when we're talking about the fundamentals of electromagnetism is we have to talk about electric and magnetic fields