How are electrons able to move from one part of an object to another and what causes this to happen?
In: Physics
Electrons are able to move around objects when the force from the nucleus holding onto the electron is overcome by some external force. When the outermost electrons are held loosely enough by the nucleus, [they will move between atoms when subjected to an electrostatic or magnetic force.](https://www.edinformatics.com/math_science/why-do-electrons-flow.html#:~:text=When%20a%20negative%20charge%20is,a%20conductor%20electrons%20are%20repelled.&text=When%20electric%20voltage%20is%20applied,move%20toward%20the%20positive%20side.)
A full explanation of this must start with defining the atom. [This Northwestern University physics document defines atoms as the building blocks for everything in the universe](https://www.nrc.gov/reading-rm/basic-ref/students/science-101/what-is-an-atom.html). They are sphere-like in shape and are made up of three smaller subatomic particles.[ Protons and neutrons make up the center of the sphere called the nucleus and the electrons fly around outside the nucleus in a sort of cloud.](https://www.qrg.northwestern.edu/projects/vss/docs/Propulsion/1-what-is-an-atom.html) A common analogy is that electrons float around the nucleus of an atom kind of like vapor droplets in a rain cloud, moving around in space while staying within the cloud itself. [The big difference between electrons and the other subatomic particles is that they are free to move around outside the nucleus](https://www.britannica.com/science/electron), which makes it easier for them to move from atom to atom.
Electrons are able to move when they “break free” from the nucleus that was holding in the cloud. The only reason that they are able to do this, is because of an outside force influencing them. [Much like a moth is attracted to a flame](https://www.physicscentral.com/explore/action/dressed-to-impress.cfm), an electron is attracted to the opposite charge, typically the protons in the nucleus. But as this accredited textbook talks about, [when the attraction force to the protons of another atom is stronger than the attraction to an electron’s own nucleus, the other atom will pull the electron away from its atom.](https://www.physicsclassroom.com/class/estatics/Lesson-1/Charge-Interactions) This will happen when a positively charged piece of metal moves close to a neutral piece of metal, some of the electrons in the neutral piece will be pulled toward the positive piece. The outside force of the positive piece allows for electrons to move around the neutral piece because it is greater than the force of the nucleus trying to hold onto the electrons. To further visualize this, see the link attached below.
This concept can also be visualized by imagining there is a dog leashed to a tree. Left alone, the dog might simply be bored, walking or standing around the tree in any random location. In this scenario, think of the dog as the electron, the tree as the nucleus, and the leash indicates how tightly bound the electron is to the nucleus. As of now, the dog is free to move around the tree as he pleases, but if he were to smell a steak at the next tree over he would be immediately attracted to it. He would want to run in that direction as if the steak was a positive charge. If the dog’s attraction to the steak is stronger than the leash holding him back, he’ll break away from his tree and run to the next tree over. The same applies to electrons, they are attracted to opposite charges and when that attraction overcomes their attraction to the nucleus they break free.
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