This video shows that current only travels in circuits or "circles". This is in a way intuitive because a battery needs the electrons to return otherwise the reactions inside won't continue (I guess).

But it is also counter-intuitive because if you think about it, an electron is always attracted to a positive ion(that's why currents of electrons occur in the first place). So the electrons on the negative side of the battery should be attracted to something positive even if there's no loop( or at least some electrons on the surface should move, right?). An example would be the lighting on the sky. All the electrons are stored in the atmosphere and dischared into the ground without an obvious circuit. Another example is the ground system in all houses (an appliance can discharge into the ground).

How can there be two ways in which electrons move?

  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$ – Dave Tweed Apr 17 at 12:07

Current absolutely can flow through the ground, and this is something you need to believe because it has safety implications: if you touch a single live wire while being electrically connected to ground, through your feet or other hand or water, it can be fatal.

There are non-dangerous uses of this phenomenon: Single wire earth return. The ground circuit used by domestic appliances does function as a "loop" when current is flowing in it, although this is less efficient than having a dedicated neutral wire.

I think the distinction you're looking for is between "current flow" and "static discharge"; lightning and charged balloons etc are the second sort. A separation of charges is built up, then a pulse of current flows as the electrons move towards the positive charge. At the end of this (fast) process, there is no more charge separation.

In normal current flow the quantity of electrons in the loop remains basically constant. In systems driven by a generator or transformer, the electrons are moved around by the moving magnetic field acting on the part of the circuit inside a coil. In systems driven by a battery, for every electron released from the negative terminal another electron is captured at the positive terminal to maintain equilibrium.


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