Question about flow of electrons and electric current

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Discussion Overview

The discussion revolves around the direction of electric current in relation to the flow of electrons, exploring historical conventions and theoretical implications. Participants examine why electric current is defined as the flow of positive charges despite the actual flow of electrons being negative, touching on both historical context and conventions in physics.

Discussion Character

  • Conceptual clarification
  • Historical
  • Debate/contested

Main Points Raised

  • Rafael Andreatta questions why electric current is considered to flow in the opposite direction to electrons, suggesting that it might be due to historical conventions established when electricity was first studied.
  • Some participants propose that the definition of current as the flow of positive charges is a convention based on the idea that things typically flow from high to low potential.
  • A later reply mentions that electricity was discovered before the existence of electrons was known, highlighting historical debates about the nature of electric flow and the initial incorrect assumptions made by early scientists like James Clerk Maxwell.

Areas of Agreement / Disagreement

Participants express differing views on the reasons behind the convention of defining current as the flow of positive charges, with some agreeing on the historical context while others emphasize the conventional aspect without reaching a consensus.

Contextual Notes

The discussion reflects limitations in understanding the historical development of electrical theory and the assumptions made by early scientists, which may not be fully resolved in the current context.

Taturana
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Why is the electric current in the opposite direction of the flow of electrons?

One may say: "Oh, because the electric current represents the flow of positive charges"...

Okay, but why don't the theory use the electric current representing the flow of negative charges?

I heard from a professor that it is because in the beginning of the study of electricity "they" used to think that the electric current was caused by the flow of positive charges... then later they realized that it was caused by the flow of electrons (in the solid conductors) and then to don't remake the theory and to don't need to rewrite everything that was writen, they defined electric current as the flow of positive charges... (this was done because the direction of the flow of electrons does not make different for calculation purposes)... is my professor right?

Thank you,
Rafael Andreatta
 
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I think it is due to convention. Usually things go from high to low. High would be considered positive. I am just guessing though.
 
Taturana said:
is my professor right?

Rafael Andreatta

Yes.
 
Electricity was discovered long before anyone had any idea that electrons even existed.
No-one could tell which way it was flowing - in fact there was a big argument about whether it was one thing flowing one way or two things flowing both ways.
James Clerk Maxwell decided it was probably just one thing and made a guess which way it flowed - he got it wrong!

Here's the book he wrote. If you ignore all the complicated maths it's interesting to read how he thought about it.

http://www.archive.org/stream/treatiseonelectr01maxwrich#page/n5/mode/2up"
 
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