Electrons
This one is automotive, but it involves cars from back in the day. This one involve cars that you need a physical key to start. Most of you remember that, right?
We all know how it used to be. When you get into the car to start, you put the key in the ignition, you turn the key, and electricity is then directed from the battery to the starter motor. And of course, it makes a complete path and goes back to the battery.
In fact, electrons begin their migration from the negative terminal of the battery, into the starter motor and then back into the battery. So that is how the flow of electricty takes place when you start a car.
Now knowing that, here is the puzzler.
If an electron were to start out at the negative, right at the negative terminal, at the battery sitting there, right? And you have 10 feet of battery cables, like 5 feet from the battery to the starter motor and 5 feet back, how long does it take a single electron starting from the negative battery terminal to reach the positive terminal? That is, to make the whole circuit?