Eli5: What is the difference between Electrical potential vs. potential energy?
In: Physics
You move something between two points and it gains or loses electrical potential energy (or keeps the same).
How much the change in potential energy is depends on where you are moving it from and to, and it depends on the thing (specifically its electric charge).
Electrical potential measures the same thing, but *factors out the thing’s charge* (by dividing by it). So rather than telling you how much potential energy changes when you move a specific thing between two specific points, it tells you how much potential energy would change when you move *any* thing between the two specific points (once you’ve factored back in the charge). It is a generalised version of potential energy.
If you want a definition, the electric potential between two points tells you the potential energy change in moving a thing *of unit charge* between the two points.
And you can do this with gravity as well; you can define a gravitational potential, where it tells you the change in gravitational potential energy for a thing of unit mass – it factors out the mass.
Mathematically, you can do this with all sorts of “field-related” forces. Any time you have a situation where the energy change *doesn’t depend on the path taken* you can define a “potential” function which will tell you about how the particular system will work. This ends up being neat as to do calculations you can ignore anything to do with the path taken, just looking at the start and end points.
And just as the (negative) gradient of the potential energy tells you the force (i.e. the force on an object will be in the direction of the steepest change in potential energy) the (negative) gradient of the potential tells you the local field strength.
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