I’ve seen descirptions of batteries, and how they kinda push electrons through wires to the other side, but how does that actually work? What’s the mechanism that makes them actually move?
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You charge up a battery by applying a voltage which creates ions and free electrons. Those are kept separate in the battery. Now you’ve got one part of the battery that contains excess electrons and is hence negatively charged. The other part of the battery contains positively charged ions and is hence positively charged.
Now you’ve got a voltage differential! In other words, you’ve created an electric field. An electric field is a force that pushes/pulls charged particles, depending upon their polarity.
The wires you use have a lot of loosely bound electrons that are free to move around. And they do all the time due to their thermal energy, but that motion is random and hence doesn’t make an electrical current.
If you provide an electric field (voltage) via the battery, those electrons still jiggle around due to their thermal energy, but they also drift in the direction of the positive battery terminal. They “drift” pretty darned fast, about 1/3 of the speed of light. That is an electrical current.
When those electrons get to the positive terminal of the battery, they de-ionize those positive ions. So the battery starts to “run down”.
Now you might ask, “Why do charged particles feel a force when put in an electric field?” and that would be an excellent question. If you come up with an excellent answer, start preparing for your Nobel Prize speech. Because the answer currently is “Because that’s the way this universe works.” You can get longer, more complex answers, but that’s what they boil down to.
You charge up a battery by applying a voltage which creates ions and free electrons. Those are kept separate in the battery. Now you’ve got one part of the battery that contains excess electrons and is hence negatively charged. The other part of the battery contains positively charged ions and is hence positively charged.
Now you’ve got a voltage differential! In other words, you’ve created an electric field. An electric field is a force that pushes/pulls charged particles, depending upon their polarity.
The wires you use have a lot of loosely bound electrons that are free to move around. And they do all the time due to their thermal energy, but that motion is random and hence doesn’t make an electrical current.
If you provide an electric field (voltage) via the battery, those electrons still jiggle around due to their thermal energy, but they also drift in the direction of the positive battery terminal. They “drift” pretty darned fast, about 1/3 of the speed of light. That is an electrical current.
When those electrons get to the positive terminal of the battery, they de-ionize those positive ions. So the battery starts to “run down”.
Now you might ask, “Why do charged particles feel a force when put in an electric field?” and that would be an excellent question. If you come up with an excellent answer, start preparing for your Nobel Prize speech. Because the answer currently is “Because that’s the way this universe works.” You can get longer, more complex answers, but that’s what they boil down to.
Batteries (and cells) have two terminals – one negative and one positive. Electrons are negatively charged and so are repelled from the negative terminal and attracted to the positive one hence they leave at the negative and re-enter at the positive.
That’s really it as far as the circuit is concerned: attraction and repulsion. The conversion of energy is a bit more complicated.
Batteries (and cells) have two terminals – one negative and one positive. Electrons are negatively charged and so are repelled from the negative terminal and attracted to the positive one hence they leave at the negative and re-enter at the positive.
That’s really it as far as the circuit is concerned: attraction and repulsion. The conversion of energy is a bit more complicated.
> What’s the mechanism that makes them actually move?
In chemistry, it is usually a redox reaction inside the battery, and a mix of magnetism, electronegativity, and conductivity through the rest of the system.
In a [redox reaction](https://en.wikipedia.org/wiki/Redox) one chemical wants to give up an electron, and another chemical wants to gain an electron. In a lead acid battery, you might have lead oxide and sulfuric acid. The lead really wants to form lead sulfate and will happily give up electrons to do it, engaging in a redox reaction. The acid really wants to break apart and form water, and will accept electrons to do it. If you push electricity back into the system you can reverse the reaction to charge the battery back up. Electrons want to flow between them to make the reaction take place.
There are many compounds you could use to make a redox reaction, but certain combinations produce a long, steady reaction we can harness in an electrical cell. A cluster of chemicals forms on one side of the battery cell, and a cluster of other chemicals forms on the other side of the battery cell, and over time the two react and use the chemicals between the two.
So for the motion, the battery has a chemical reaction going on in the middle and that makes a charge (magnetic or electric, depending on how you look at it) with a positive side and a negative side. As above, electrons want to flow between them to make the reaction take place. Wires provide an easy path to move from one side to the other. Metal conducts electricity, easily taking and releasing electrons much like a bunch of marbles stuffed in a tube. You can put an electron in one side of a metal wire and it pushes the electrons on the next one, which pushes the next one, which pushes the next one, until one pops out the other side.
Components along the wire take advantage of those electrons moving through the metal pipe, they might use it to make a motor turn, or to generate heat, or to make light, or to run an electrical switch or transistor, or something else. Electronics are often explained in simple forms using the model of water moving through a system in a similar way.
> What’s the mechanism that makes them actually move?
In chemistry, it is usually a redox reaction inside the battery, and a mix of magnetism, electronegativity, and conductivity through the rest of the system.
In a [redox reaction](https://en.wikipedia.org/wiki/Redox) one chemical wants to give up an electron, and another chemical wants to gain an electron. In a lead acid battery, you might have lead oxide and sulfuric acid. The lead really wants to form lead sulfate and will happily give up electrons to do it, engaging in a redox reaction. The acid really wants to break apart and form water, and will accept electrons to do it. If you push electricity back into the system you can reverse the reaction to charge the battery back up. Electrons want to flow between them to make the reaction take place.
There are many compounds you could use to make a redox reaction, but certain combinations produce a long, steady reaction we can harness in an electrical cell. A cluster of chemicals forms on one side of the battery cell, and a cluster of other chemicals forms on the other side of the battery cell, and over time the two react and use the chemicals between the two.
So for the motion, the battery has a chemical reaction going on in the middle and that makes a charge (magnetic or electric, depending on how you look at it) with a positive side and a negative side. As above, electrons want to flow between them to make the reaction take place. Wires provide an easy path to move from one side to the other. Metal conducts electricity, easily taking and releasing electrons much like a bunch of marbles stuffed in a tube. You can put an electron in one side of a metal wire and it pushes the electrons on the next one, which pushes the next one, which pushes the next one, until one pops out the other side.
Components along the wire take advantage of those electrons moving through the metal pipe, they might use it to make a motor turn, or to generate heat, or to make light, or to run an electrical switch or transistor, or something else. Electronics are often explained in simple forms using the model of water moving through a system in a similar way.
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