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Electric Potential and Charge Flow:
Electric potential is a location dependent quantity that describes the amount of electric potential energy per charge possessed by a charged object at a given location. In order for charge to flow from one location to another location, there must be a difference in electric potential between the two locations. If there is a difference in electric potential between the two locations, then charge will spontaneously move from the location of high potential to low potential.
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An analogy comparing the flow of water in a water park to the flow of charge in a circuit is often used in a physics class. Both situations involve the flow of a fluid through pipes or a conduit. In the case of water flow, such flow would not be possible unless two ends of the pipe were held at different water pressure or gravitational potential. That is, the potential energy possessed per kg of water at the top of a slide must be greater than the the potential energy possessed per kg of water at the bottom of a slide. With this difference in pressure or gravitational potential established between the two locations, water naturally flows through its circuit from high potential location to low potential location. In the same manner, there must be a difference in electric pressure or electric potential energy between two ends of an external circuit in order for charge to flow through the pipes or wires. Of course to maintain such a difference in water pressure or potential at a water park, a water pump must do work upon the water to move it from the low energy to the high energy location. And in the same way, a charge pump (a.k.a. a battery) must do work upon a charge in a circuit to move it from the low energy to the high energy location.
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