by johncarlosbaez on 6/21/24, 3:16 PM with 242 comments
by throwway120385 on 6/21/24, 9:49 PM
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.
by sobellian on 6/21/24, 10:03 PM
by CapitalistCartr on 6/21/24, 9:16 PM
by AnotherGoodName on 6/22/24, 12:29 AM
Eg. imagine the earth below you shielding you from a force that otherwise pushes all mass in all directions constantly. You’re now more shielded from the push in the direction of the earth so you feel pulled that way.
It’s the same thing. Just a sign change from a convention we had no real basis to believe one way or the other.
by vagab0nd on 6/22/24, 3:26 PM
by nitwit005 on 6/21/24, 9:11 PM
Although I suppose we essentially did that when naming the quarks.
by lupire on 6/22/24, 3:48 PM
In some systems, there really is a positive. Such as temperature e with absolute 0, and where numbers multiply together into the same dimension so multiplication is not symmetric under sign change. (Although this is usually also a type error!)
In other systems, there are a pair of opposite directions, and it's not correct to consider one positive one negative, but merely opposite. Both poles should be signed, and values never multiplied into the same dimension, and names distinctly, even if we must choose a convention when modeling them with computers.
by imchillyb on 6/21/24, 9:53 PM
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.
by michaelrpeskin on 6/22/24, 4:38 PM
The rule of thumb I always use is that at household voltages and currents in copper the electrons move a few tens of microns per second. If your lights are on all day the electrons might move a meter or so from where they were when you turned the switch on.
by fhars on 6/21/24, 9:11 PM
by Am4TIfIsER0ppos on 6/21/24, 9:51 PM
by beryilma on 6/22/24, 12:27 AM
Since electricity and magnetism are really fields per Maxwell equations, the current flow and other electrical things that we attribute to the inside of the wire are really happening outside of the wires as electric fields.
They have a much better explanation than mine certainly...
by yarg on 6/23/24, 11:01 PM
The convention by which an electron is negative and a proton positive is arbitrary and could be flipped;
Indeed it could be replaced by any pair of charge definitions x and !x.
However that has zero impact on the direction of a current's flow through a conductor (that's a physical process and is not defined or impacted by the established conventions).
I'm not sure what the real answer is, by my high school physics teacher told me that the charge is carried not by the electrons, but by the gap (a virtual particle) that flows backward as the electrons move forward.
(Similar to the way that a gap in traffic propagates backwards.)
I have no idea how wrong this is, so hopefully check the comment below from whoever bothered to correct me.
by daxfohl on 6/21/24, 10:59 PM
by NegativeLatency on 6/21/24, 8:37 PM
by arnarbi on 6/21/24, 10:15 PM
Like bubbles rising in water, the holes “travel” opposite the potential that’s pulling the surrounding electrons the other way.
by tdeck on 6/21/24, 10:01 PM
I read somewhere that this was also common in the USSR but can't find any references. Perhaps someone here will remember.
by MarcScott on 6/22/24, 5:14 PM
You could watch them hold up both hands, wondering which one to use, then trying to dislocate their wrists as they aligned fingers and thumb with the diagram on the exam paper.
by DidYaWipe on 6/23/24, 5:16 AM
by Yaa101 on 6/22/24, 1:06 AM
by boring-alterego on 6/21/24, 10:48 PM
You'll find basic electrical circuits books sometimes have an electron flow edition.
by mikewarot on 6/22/24, 7:32 PM
by kazinator on 6/22/24, 11:01 PM
by loandbehold on 6/22/24, 12:30 AM
by bmacho on 6/21/24, 9:17 PM
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 additive structure of real numbers / integers is very reasonable. (You could use red and blue numbers, but that's not a widely used structure.)
So you shouldn't say "electron is negative". That's weird, confusing, misleading, and trolling.
by thriftwy on 6/22/24, 5:19 PM
by Charon77 on 6/23/24, 4:44 AM
by bilsbie on 6/22/24, 12:42 AM
Anyone know?
by noobermin on 6/22/24, 2:28 AM
by hiccuphippo on 6/21/24, 11:15 PM