"While consulting for Holt/Rinehart I considered the typical hydraulic analogy to explain electric ciruits. I found a better one: electricity is like the molecules in a loop of rope wrapped around pulleys. It's like the rubber of a conveyor belt: when the drive roller turns, all the other rollers turn as well. When internet came along, I started pushing this analogy all over Usenet forums. It slowly caught on. Then I came up with another version: electricity is like a rubber bicycle tire: push it in one place, and all the rubber must turn as one. Look around the www today, and see how far these ideas have spread."
"If electricity is like gravity, what are the similarities?
G (gravitational acceleration) Field
Potential Energy Voltage
What are the differences?
"Main one is that electricity can be positive or negative, so attractive or repulsive... gravity that we deal with on earth has a constant field (because the distances are so great), but electric fields change with distance."
A page that discusses this analogy and how it may be useful to help children learn about electricty
"Electricity is like water and pipes. Voltage (E) is like water pressure. Amperage (I) is like volume of water. Wattage (P) is like the total amount of water / electric power delivered whether at high pressure through a small hose/wire or low pressure through a large hose/wire. The formula for wattage is P = I x E or Watts = Volts x Amps. You can start a car with lots of amps but only 12 volts (and a big wire) or run a power saw (about the same wattage) with 120 volts at a few amps (and a small wire). As long as the motor, light or machine at the end of the line is made for the right voltage it will work if you have the right voltage, enough amperage available and a large enough wire from the source. "
"In a way, electricity is like natural gas by wire," Moore said. "If the economics don't work to actually build and sink a pipeline to points in Maine for natural gas, the next best thing is to take advantage of natural gas pricing through electricity."
"In an AC system, the charges of electricity move back and forth over a short distance. In other words, they sit inside the wires and vibrate. That's what AC or Alternating Current is all about. The electricity does not move forward at all (if it did, that would be a direct current or "DC.") Yet as the charges of electricity are wiggling back and forth, the electrical energy moves forward rapidly. Only the electricity "alternates." The electrical energy does not; the energy flows continuously forwards as waves. (If this is confusing, think of sound which moves through the air. Electricity is like the air which is vibrating. On the other hand, the electrical energy is like the sound waves which fly through the air.) Just as sound and air are two different things, electrical energy and electricity are two different things. "
"Electrical circuit analogies for several engineering disciplines have been developed over time. These are summarized in the table below prepared by Dr. Holbert. The mechanical analogy used is the mobility analogy in which the physical analogies are sacrificed in favor of creating equivalent mathematical relationships which hold in network analysis."
The linked page contains a table that mathematically relates electricity to mechanical, hydraulic and thermal energy.
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.