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What causes electric charges? Repulsion and attraction?

  1. Mar 23, 2012 #1
    Hi, I'm an undergraduate biologist student. I was studying chemical bond, but, while trying to understand it, I couldn't really get what causes the electric charges, what seems essential to me. So, someone can explains, in the simplest way as possible, what is electric charge? What causes it? Why there is repulsion and attraction? In my searches I found out something about virtual photons, hypercharge, weak isospin, vacuum, but I couldn't really follow what it meant because it was in a high technical language. Thank you in advance, and sorry if I'm not posting this question in the right place :)
  2. jcsd
  3. Mar 23, 2012 #2
    Well, a lot can be said about electric charge and electromagnetism in particle physics, but when it comes right down to it, there is really no answer that doesn't just shift the question of "why is nature this way?" to a more difficult technical place, and which is not really much more philosophically satisfying than your current question.

    Electric charge just "is". It is one of the fundamental ingredients that we put into our models, as a postulate, and then explain the rest of the world using it (I lie a little bit but not very much). To go beyond this, we really have to start looking towards grand unified theories and string theory or something.

    There is an interview Feynman once did with the BBC in which he tries to explain the difficulty with such questions, it is really quite wonderful, I highly recommend watching it: http://www.youtube.com/watch?v=wMFPe-DwULM

    It is a deep rabbit-hole you are peering down, and physicists are not actually so much further down it than you might think. They are just much better at explaining 'how' all these things work. If you want to know more about 'how', we can certainly go there.
  4. Mar 23, 2012 #3
    Thank you for the reply :smile: I never saw that particular Richard Feynman's video, and I really admire him, so, it was great seeing my question being discussed there.
    Well, I understand what you said, I guess, and somehow I knew it was a trick question by the start. I still have curiosity about electric charges, electromagnetism, photons, light and all, of course, but I suppose it's too complex to go really deeper without having a good physics knowledge beforehand.
    Anyway, if someone has any new information to share about the subject, it would be amazing :) I'll never have a full answer, naturally, it probably doesn't exist, but understanding a little more is always great. Like, what's the connection between virtual photons and electric charges? etc. ( maybe this question is kinda already wrong, I don't know, I just read it somewhere and may be confusing myself)
  5. Mar 23, 2012 #4
    No problem.

    It depends what kind of detail you want to know things in. I think you can get the basic gist of it all with even a high-school level of physics knowledge, with a little work.

    Well your electric charges create electric fields (and magnetic ones if they move), and the simple thing to say is that at the quantum level we can describe electromagnetic fields as being made of virtual photons. It is a little bit tricky because virtual photons mostly make sense at reasonably high energies and with very weak fields, and usual classical electric and magnetic fields are nothing of the sort, but the picture can still be somewhat helpful.
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