[gus_massa]

Those videos are misleading. Electrons flow inside the wires. They just flow much slower than what you would expect. When you close a circuit, the information that it was closed goes very fast but the electrons flow slowly.

(It happens also with water, if you have the shower with only very hot water and you open the cold one, the output of the shower changes almost instantly but you need like a second to get the mixed water with that is warm.)

What flows outside the wires is the energy. It's very unintuitive but it's true. Feynman has a nice lecture about it. But note that most of the energy flows very close arround the wires, a very small part wanders far away.

There is an exception when you have a radio transmissor with an antena and a reciver. Then the energy flows just through the air (or vacuum). Also when you have a light lamp or a laser.

Actualy every electric circuit emit some radiation as a bad radio tranmisor. But most of the times you can ignore it.

[int_19h]

The more straightforward analogy with water is a pipe that is completely filled. Even if the water moves very slowly, the fact that it has started moving is immediately detectable as some of it will start spilling from the other end of the pipe right away. If you have a turbine installed at the other end, it will also start spinning right away. Moreover, if you make the pipe wide enough, even very slowly moving water will move a lot of volume in a short period of time, and thus transmit a significant amount of energy to the turbine.