I used to teach overseas, and here is how I made a visualization for my
trade school students: We had one person be the generator, with a box of
ping pong balls. When he would
"crank up" one ball was passed to the next person in a circle, (circuit),
who already had two ping pong balls, one in each hand. He was told he could
not take one from the generator person until he got the one in the hand
handed off to the next person in the circle, and the last person had handed
one off to the generator, thus creating a hole. Now the ping pong ball
represented the electron, and although the original one did not instantly
make its way around the circle (circuit), as the handoffs continued, the
last hand on the other side holding a ping pong ball (electron) dropped that
one back into the generator box. Everything balanced out, but current and
apparent hole locations had progressed in opposite directions.
It is not a perfect analogy, but certainly showed that one electron does not
do all the work, but simply nudges its neighbor over to another atom, and
takes its place. I found it was much easier to teach electric current flow
after this exercise in the lab. The students enjoyed the departure from
lectures and textbook reading.
73,
Stuart K5KVH
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