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What is electricity?

  1. Nov 26, 2011 #1
    Hi guys,

    I'm studying as an Electrical Engineer and I have very little knowledge in this subject. Please explain to me what electricity is, how it is created, and how does it work to power electronics and stuff(be as descriptive as you can).

    ..and also, if you don't mind, please give a description of yourself(i.e. teacher, engineer, physicist, etc) or if you have an b.s. , m.s, or phd in something.

    Note: I may be quoting you.


    Thanks for your help! :)

    ~
     
  2. jcsd
  3. Nov 26, 2011 #2

    mathman

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  4. Nov 26, 2011 #3
  5. Nov 26, 2011 #4
    Electricity in it's most basic description is the flow of charged particles, that are usually electrons, through a material.

    For instance, a copper wire is basically a transport system for electrons.

    There are many practical applications for this. But let's start with an electric generator.

    Essentially, mechanical energy is used to spin a magnet around inside of a circle of copper wire. This generates an electromagnetic field that introduces energy to the system. Thus kick starting the flow of electrons.

    The electrons flow out of the generator into either some sort of storage device like a capacitor or battery system or is simply left to flow into wiring that is connected to electronic devices.

    Now, let's take an incandescent lightbulb, for example. The electrons flow through the wire into the bulb where, through the manipulation of current from specific types of metal in a structure called the filament, energy is shed in the form of light and thermal radiation.

    An electric motor is basically the opposite of a generator. Using electricity to manipulate magnetic charge, one can alternate magnetic fields (or turn one off while turning on the other) in a circle of material surrounding a central shaft that is magnetized in some way. This spins the shaft, producing mechanical energy that is then used to do things like operate the blades inside a blender or wheels of a radio controlled car.

    It get's more complex than that and I can help provide more in depth explanations. And I'll come back and attempt to explain things like solid state electronics if no one else does. But I'm going to the bar now. lol

    I don't have a degree yet. Right now I'm a political science major (so forgive me for any shortcomings in my descriptions). But I was once an astronomy major and will be again next semester.
     
  6. Nov 26, 2011 #5
    Also, if you really want to have a further understanding of this, I recommend reading Quantum Electrodynamics (QED) by Richard Feynman. It's a series of lectures put into book form.
     
  7. Nov 27, 2011 #6
    Thanks mkarger for the info. I'll surely be putting it in my essay. Your information is very useful but it has sprung up more questions.

    If it doesn't trouble you so much, can you explain further about how spinning a magnet in a coil of copper wire produces an electromagnetic field. What is an electromagnetic field?
    And, what is energy?

    You also mentioned that electricity can be used to manipulate magnetic charge therefore manipulating magnetic fields, resulting in mechanical energy; Can you explain more about how electricity manipulates magnetic charge? And how manipulating magnetic fields cause movement?


    Again thanks for the help. As much information as possible would be helpful :)
     
  8. Nov 27, 2011 #7
    A few equations, called Maxwell's equations, detail the connection between electric and magnetic fields. A spinning magnet would have a time varying magnetic field. This in turn induces an electric field which drives a current through the wire. Maxwell's equations express the experimentally observed behavior of electric and magnetic fields mathematically. Since they are connected in this way, people call this the electromagnetic field.

    Since the time of Maxwell, it was known that electromagnetic fields propagate as waves. (Some manipulation of Maxwell's equations results in a partial differential equation known as the wave equation.) Even more astonishing is that these waves are waves of electromagnetic radiation, which includes light!

    Once we get to this stage, everything gets a lot more complicated. The behavior of light is a fundamental question of physics, and the fields of quantum mechanics, relativity and quantum electrodynamics relate together deeply to try to explain the behavior of the electromagnetic field.

    Einstein showed that electric and magnetic fields were the same thing from different reference frames, and quantum mechanics showed us that a wave of light is actually composed of photons, which are quanta of light. Quantum electrodynamics showed how the electromagnetic field is "felt" between two particles as an exchange of photons.

    I don't know too much about relativity or QED because I am only an undergrad, but those are some of the things that I have learned about electricity, magnetism, and light.
     
  9. Nov 27, 2011 #8

    ZapperZ

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    So in other words, we will be the ones doing your assignment for you? This is a very strange class. It appears as if it doesn't require that YOU have a good understanding of the topic that you're writing about, just the ability to parrot it in an essay.

    Zz.
     
  10. Nov 27, 2011 #9
    No. I would still be learning. Interviewing is another form of research. I ask you guys the questions and you feed me the info. And, you will not be doing my assignment for me, I'm only quoting you guys as "evidence". It's not like the entire paper is a summary of what you guys wrote. Also, I do not want you guys to do the research for me, I just want you guys to write down what you already know.
     
  11. Nov 27, 2011 #10

    ZapperZ

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    And your professor is OK with you quoting strangers off a public forum?

    I know that the standard that people use nowadays as valid sources is falling rapidly, but this is going way too low.

    Zz.
     
  12. Nov 27, 2011 #11
    Well, my paper is a "discovery" research paper. I'm supposed to explore a topic important to me and in the end gain significant knowledge on the topic. I might take a wrong turn with misleading, unreliable information but hopefully with thorough research I will get back on the right track. I guess that's part of the "discovery" process. Note that my entire paper will not be based solely off of interviews from strangers.

    Thanks to all of you for your responses.
     
  13. Nov 27, 2011 #12
    A magnet is basically dipole in the most standard sense. This results from waves leaving one pole at an angle almost perpendicular to the object. They curve further and further towards a parallel line running down the side of the object until they curve, again, back towards being perpendicular with the opposing pole where they reenter the object.

    http://www.magnetic-shield.com/images/faq/flux-images.jpg [Broken]

    This can be on an extremely small scale like pellet sized magnets. It can also be on the scale of planets and even larger systems.

    The dipoles exist because of negative and positive charge.

    However, you can manipulate magnetic objects into layers, like a hard drive or refrigerator magnet, that has a different composite magnetic fields (see below).

    The reason for these magnetic fields varies on the object in question. The Earth, for instance, has a rotating core made of metal that spins in such a way relative to surrounding layers that it actually generates a magnetic field just like an electrical generator.

    Permanent magnets are the result of aligning the electrons within individual atoms in a material. As the electrons spin and interact with their surroundings, they generate dipole magnetic fields. By aligning the electron magnetic fields, their fields are compounded and the object becomes magnetized.


    As for electrical generators, the magnets have an inherent magnetic field created from processes mentioned above (generally speaking. There are more complex systems that have induced fields). This field carries energy in the form of electromagnetic radiation. As this field rotates and is pushed through copper wires, energy is introduced to the wires and causes excessive charge in the atoms and, more specifically, the electrons. The electrons are essentially kicked out of the individual atoms, that are attempting to reach equilibrium, where they then interact with other atoms. This process carries electrical charge through the copper wire out of the generator.

    I'm not going to answer the rest of your questions because the other posters here have a valid point. You have gotten a good amount of info. It's important that you do your own research. Otherwise you'll never truly understand it all.
     
    Last edited by a moderator: May 5, 2017
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