In class, we referenced a hydraulic analogy to current flow in circuits. This analogy has deep historical roots but has long been controversial (“does it do more harm than good?”). The derisive term “drain-pipe theory” for this analogy is attributed to the British physicist Oliver Lodge.
My personal opinion is that this analogy is very useful to solidify the basic physical concepts of charge (total quantity of charge like gallons of water), current (rate of flow like gallons per second) and voltage (energy level difference per unit charge like elevation in a gravitational field). Of course, like any analogy (or physical model for that matter), this breaks down, when you think about it more than a little. In fact, the analogy very quickly loses its usefulness when you start looking for hydraulic analogues of specific circuit elements such as batteries and resistors, see e.g. here for the kind of unproductive knots you can easily find yourself tied up in.
That said, this analogy will work fine at a superficial level for almost everything we do this semester (up until the very last week in fact), and the gravitational potential paradigm referenced in the Wikipedia article has the official HawkEE endorsement!
To start with, you may find the animations here useful to visualize the concepts of current and voltage.
Happy Plumbing with electrons!
hawkee 