Why is electricity so hard to understand? (1989)
&gt; ...mistaken belief that energy flows out of a battery through one wire, then flows back through the other. The charges do this, while instead the energy flows along both wires in one direction, from source to load.<p>Has somebody a good visual analogy for this in another medium?
I mean I know that this is a case but I can not visualize the energy flowing on both sides out of the source with the medium only moving out on one side.<p>I will try for myself:<p>Say I pump a lot of water in a circle by moving a pump by hand. I put some energy into the system. By pumping I push water molecues out one side of the pump and pulling them in on the other side. That creates a pressure difference inside the water. Even if I pump the water really slow, that pressure difference propagte with the speed of sound through the water. That pressure difference is positive one the one side of the pump (water is pushed) and negative on the other side (water is pulled). Somewhere on the other side of the pipe circle the pressure differences meet cancel each other out. So the pressure difference is the energy moving through the system in both directions. But the water itself only moves in one direction.
But now we have two kinds if energy in the system. The pressure wave and the kinetic energy of the water. 
If I keep pumping the water will speed up faster and faster. I guess that&#x27;s the analog to a glowing wire. 
But if a put a turbine into the water the flow of water will be slowed down because the kinetic energy of the water is extracted by the turbine.
Now if the water is at rest and the turbine as well and I now start pumping the pressure difference will flow in both directions to the turbine. It will start spinning as soon as the pressure differences meet there.
If the turbine is not opposite to the pump the pressure differences will take different amounts of time to reach it. But the turbine will already start moving when hit by the first pressure difference by absorbing it the (pressure wave stops there) and then latter be hit by opposite pressure difference and move again.<p>So far correct?<p>So in an ideal system the water would not move at all but only the pressure difference would propagate and be consumed by the turbine.
But that would mean that the turbine energy leaves the system completely -&gt; the turbine does not even turn because it&#x27;s energy is 100% extracted by it&#x27;s consumer.<p>So in this example flowing water always represents some kind of loss&#x2F;inefficency.
The goal would be to maximize the pressure difference to propagate but the minimze the water flowing.<p>Is this how you could explain alternating current for transportation of energy?