Explaining Voltage/Current/Resistance to non-physicists

[vortmax]

I'm a TA for a sophmore level E&M lab course that is taught independent of the lecture. So most of my students are seeing these concepts for the first time in the lab setting (learning through discovery).

Many of them are having problems visualizing the concepts of the voltage, current and resistance. However, most of them have had mechanics, so they understand the concepts of potential energy and work.

I understand the fundamentals of E&M, but I'm having a hard time describing it in ways that the students can grasp and internalize. I've managed to make some promising headway by making the parallel between electrical potential and gravitational potential and relating that back to voltage, but am not sure how (or if it's worthwhile) extending that metaphor further.

So, can anyone have a solid, basic description of voltage, current and resistance that would make sense to someone who has had basic mechanics?

 

[chroot]

The most useful (and common) analogy is that of water. Batteries and other voltage sources are pumps. Voltage is water pressure. Current is the flow of water. Resistance is a restriction in a pipe, or a sponge shoved into the pipe.

- Warren

 

[Born2bwire]

I agree with chroot, the water analogy is usually the most accessible. For a more physically correct description, familiarize yourself with the Drude model and you could use that to explain the dissipation of potential energy throughout the circuit and thus explain resistance, current and voltage drop.