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I am a n00b to physics. What physics I know comes from high school and popular science books.

At school we were taught about atoms and what make up atoms, but we weren't actually told what the particles were!

So sure an atom has electrons orbiting around a nucleus made of protons and neutrons, but what exactly is an electron?

And if we don't know, how can we fire them from guns, like they do in experiments ... etc

Any clarification on this would be great.

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    $\begingroup$ I don't think anyone will give an answer as good as the first paragraph on the Wikipedia article: en.wikipedia.org/wiki/Electron $\endgroup$ – kd88 Jan 27 '14 at 15:07
  • $\begingroup$ :( but that is gibberish to non-physicists. Should I just accept the fact that those not in physics won't know what an electron is? :( $\endgroup$ – J86 Jan 27 '14 at 15:20
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    $\begingroup$ Physics says how electrons behave according to some theory, not really what electrons "are". $\endgroup$ – antin Jan 27 '14 at 15:28
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    $\begingroup$ To expand on antin's explanation a little bit, the question itself is a little meaningless in general -- what would be a satisfying answer to the question "What is an XYZ?" ? The answer to this for almost anything would be a combination of what it does, how it behaves, or what it looks like (if you can see it). $\endgroup$ – YungHummmma Jan 27 '14 at 15:48
  • $\begingroup$ Again Nice :) Love it ! $\endgroup$ – J86 Jan 27 '14 at 15:48
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It is a fundamental particle with the properties of an electron (one electron charge, one electron mass etc.). Electrons are extremely small and considered to be point particles, but their wave function can be dispersed over a large area (entire atom or even molecule).

A proton is not a fundamental particle since it is composed of three quarks (these quarks are fundamental).

All electrons are identical to each other. So if I have two electrons there is no experiment that I can perform to tell them apart. If there was they would behave drastically differently.

Electrons are fermions which means that no two electrons are allowed in the same place at the same time. If they were then there would be no chemistry since all electrons would drop into the lowest energy atomic shell.

Electrons also have a property called spin. It is LIKE the particle is spinning on its axis (despite being a point particle with no axis), it is only allowed to spin at one speed and in one of two directions.

but we weren't actually told what the particles were!

Well this is a deep philosophical question with no universally agreed answer.

Classically we imagine it is just a tiny charged billiard ball that bounces around, but this view is very wrong.

In quantum mechanics an electron is considered to be a wave function that interacts with other wave functions, all of which is treated very mathematically, with no classical analog.

In Quantum field theory and string theory the electron is considered an excitation of a string or field. Imagine a belt with a twist in it, the twist is the electron, it can move from one end to the other, it can be in a very spread out or exist in one spot, and if it meets a twist in the opposite direction then the both disappear. The twist in the opposite direction being an anti particle positron.

And if we don't know, how can we fire them from guns, like they do in experiments ... etc

If we don't understand something there is nothing stopping us from doing experiments and firing them from guns. In fact once we do understand something that's when we stop doing experiments.

If I don't know what a platypus is there is nothing stopping me firing it in a gun.

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  • $\begingroup$ I've been wondering all about this as well. Exactly what are "electrons"? All I can conceive in my head is a flat surface (zero charge) and an electron being a downward dimple. When two come close, they're field's start to combine, causing them to each move back "up" the hill and away from each other's potential wells. Is that even remotely useful as a visual analogy? Obviously this is a 2-dimensional visualisation too... $\endgroup$ – Nick Bedford Feb 19 '15 at 3:16
  • $\begingroup$ How spin of electron is "like" spinning on its axis? Spin of particle have quite nothing to do with space; spin is about how to interact with magnetic field. $\endgroup$ – Shing Jan 10 '17 at 7:25
  • $\begingroup$ To add: physics is also not sholastic. It is not based an dogma (except causality maybe). If in 10 years we find that the electron is not elementary, then the explaination will change (and the domain of validity of the current model will be known) $\endgroup$ – lalala Sep 12 '17 at 5:42

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