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What exactly is the positive/negative charge in batteries?

  1. Dec 21, 2013 #1
    In batteries, what exactly do we mean by negative and positive charges? My understanding is that the negative charge of the anode is basically an atom with an extra electron in the last orbital that it would need to lose to reach a more stable state. and a minus electron in the last orbit of the positively charged atoms in the cathode that it needs to get? and so the electrons keep flowing and interchanging cuz the atom is trying to reach a stable state. Is this correct or am I messing things up?

    and if my understanding of positively/negatively charged atoms is correct, What do we mean by saying that the electron in itself has a - charge?

    What about capacitors? What are the charges on capacitors side? I don't mean whether they're negative or positive charges. I'm more confused about the nature of these charges. what exactly is a charge?
  2. jcsd
  3. Dec 21, 2013 #2


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    In batteries,a chemical process is responsible for getting electrons from one electrode and giving it to another electrode and that electron travels to its new electrode through the circuit,making what we see as an electric current.The terminal injecting the electron to the circuit is the negative terminal and the other terminal is the positive one.Study about Fuel Cells.
    In capacitors,the terminal which is connected to the negative terminal of the battery receives electrons from it and becomes negative because of the excess electrons.This negative charge builds up an electric field which causes the electrons in the other terminal of the capacitor to Retreat,making the terminal positive!
  4. Dec 22, 2013 #3


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    Charge is really just a property that some fundamental particles have or don't have. Like many things we know what but not why. We know there are two types of charge in the universe but the decision to call electrons "negative" is arbitrary.
  5. Dec 22, 2013 #4


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  6. Dec 22, 2013 #5


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    Let's look at an electron. It's a fundamental particle that has certain properties associated with it, such as mass. All electrons have mass, and all have the same mass. In addition, there are other properties such as spin and charge. All of these properties are ways to explain how electrons interact with each other and other particles. For example, if we apply a force to an electron we would measure a certain amount of acceleration that requires us to have the concept of mass to explain. (As the equation F=MA shows, which says that force is equal to the mass of an object times the acceleration it is experiencing)

    Way back a couple hundred years ago when scientists were first figuring out what electricity and magnetism were, they found out that it made sense to define a objects as having one of two types of "charge", either positive or negative, and that object possessing different charges were attracted to each other while objects with the same type of charge were repelled. Eventually scientists discovered that matter was made up of fundamental particles and that this "charge" happened to be a property that applied to these particles. Having more electrons than protons gave an object a negative charge, while having more protons than electrons gave an object a positive charge.

    That's pretty much it. Charge is simply an intrinsic property of certain particles. If a particle has a charge, specifically an electric charge, then it can interact via the electromagnetic force. If not, then it can't. (Though certain particles, like neutrons, can still interact via the EM force even though they are electrically neutral since they are not fundamental particles, but are composed of electrically charged quarks)

    So you can say that charge is the property of a particle that determines how it interacts with other electrically charged particles.
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