# About electric current analogy

my teacher gave me this analogy to the electric current , the wire is like a pearl necklace where the pearls can move, the current or the movement of electrons is like putting your fingers between 2 pearls separating them then you start taking one pearl from the right of your finger and push itto the left of your finger starting making the pearls to move, is this analogy right?

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I don't think so. Try this: put enough marbles to fill some length of plastic tube. Then, with your finger, push the marble on one end into the tube. Watch how the marble you push, pushes onto the next marble, and so on down the line, until the last marble falls out of the tube. The force you applied on the first marble is the $Voltage$, the number of marbles that passed any given point in the tube every second is the $Current$, and the friction of the tube on the marbles, slowing down their movement, is the $Resistance$. –  Greg Jun 6 '13 at 4:59
but as soon the last marble falls out it's replaced by another one from the other side to the tube right? –  homer Jun 6 '13 at 5:13
Actually it's the same marble that falls out that comes in from the other side - the idea is that the tube is closed, and there is some height difference between points in the tube. So imagine a tube that starts at some height, then goes down, and at the very bottom, is connected by more tube back up to close the loop. The marbles that start at the top will obviously fall down to the bottom...what can bring them back up to the top again? You have to 'push' them back up, with the so-called electromotive force. This is the voltage that the battery provides. See this: tinyurl.com/le7ybqg –  Greg Jun 6 '13 at 5:26
It was always a good analogy to water (that's why we say that current flows). You have a pump (voltage source) which takes water from earth to some height (voltage level). If it can fall down it does with some speed -- current. This analogy was so strong that it was very hard to understand AC: why should we put water 50 or 60 times a second in opposite directions? –  Voitcus Jun 28 '13 at 7:46