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Why does current flow the opposite way from the electrons?
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Re: Why does current flow the opposite way from the electrons?
#12Re: Why does current flow the opposite way from the electrons?
#13Because he didn't know anything about electrons, and the experiment he did involving rubbing amber and glass rods on fur and silk cloth only showed that something was transferred between the two materials, and that when the material containing the substance was brought near to the other material containing the other substance, the property conferred by the substances appeared to negate. If you read Teaching Introductory Physics the author very clearly points out that there is no way of knowing the direction of the charge. It must instead be decided by convention. And Franklin simply chose a convention that we stick with.
This is where the need to use mathematical formalism to describe physical concepts becomes clear. Numbers and numeric quantities aren't a real thing that exists in the world. They exist only in our minds. And so does the concept of negation. Calling electrons "negative" is simply a tool for us to model how the substance behaves when it interacts with an "opposing" substance using numbers. We could just as easily have called it "black" or "white" charge, except that we then need to adapt arithmetic and algebra and calculus and so on to work with the concept of "black" or "white" quantities if we are to use them to understand the substance of charge.
Re: Why does current flow the opposite way from the electrons?
#14Could be worse. They could have chosen any term implying opposite. We could have had left and right handed charges. Although I suppose we essentially did that when naming the quarks.
Or amino acids. Many have a D (Dextrorotatory = right) or L (Levorotatory = left) form, indicating into which direction they rotate polarized light.
Re: Why does current flow the opposite way from the electrons?
#15Electrons were not discovered for more than a hundred years after his death. How could he have done the "right" thing other than by chance?
Re: Why does current flow the opposite way from the electrons?
#16If one takes into account the field dynamics, the electrons are indicators of electromotive force and not the originator. The electromagnetic field connects the circuit and then _drags_ the electrons with it in a flow.
Technically the opposite flow theory would be the opposite reaction to the field drag. Every action has an equal and opposite reaction. The equal reaction would be the electrons being dragged with the field. The opposite would be the current flow we observe.
I can't wait until we can more clearly and accurately view the different fields that make up everything we know. It's fields all the way down.
Re: Why does current flow the opposite way from the electrons?
#17Could be worse. They could have chosen any term implying opposite. We could have had left and right handed charges. Although I suppose we essentially did that when naming the quarks.
The worst part is that up and down are not really opposites. Down is up on the other side of the world.
I'm not sure I follow you there. In that sense, "down" means toward the center of the gravity well. It is the same regardless of which side of the world you're on. If you mean that "down" changes direction with reference to a straight line, ok. But how does that make "up" not the opposite of it?
Re: Why does current flow the opposite way from the electrons?
#18> that makes electrons negative, and apparently nobody knows why When there is a symmetry, there are choices, all the time in math, and sometime in physics too. Also I don't like calling electrons negative, they are not. Maybe you can say that their charge is -1, when you model charge with the additive structure of real numbers / integers, and you choose the protons charge to correspond to 1. Modeling charge with the…
Red and blue integers : there is red 1, red 2, ... 0, blue 1, blue 2, ... . Addition and subtraction as you expect. There is no ordering, also no multiplicative structure. There are 2 isomorphism into the additive structure of the integers. ( Red and blue reals are defined similarly.) I find this structure to model charge better. If not for else, at least it prevents you to ask silly questions about charge.
So you mean red like warm water and blue like colder? Warm is + and cold is -.
Re: Why does current flow the opposite way from the electrons?
#19Everyone is giving correct answers so I'll just add something: in some parts of the world the convention has been to consider current flowing from negative to positive. For example in Scotland it's often taught that way apparently: https://www.mrsphysics.co.uk/blog/why-electron-flow-scotland...
I read somewhere that this was also common in the USSR but can't find any references. Perhaps someone here will remember.
Re: Why does current flow the opposite way from the electrons?
#20Charge carriers aren't always electrons anyway, so you're restricting yourself by thinking of current as electrons moving. Even in the usual case where electrons are the charge carrier, it is only the small net movement of zillions of electrons back and forth which produces a current. So in any case current is a macrostate and electron movement is a microstate, and sign convention won't change that.