My BIG question is : why does positive battery cable in a car is directly connected to the starter to crank the engine and does that mean the current actually flows from positive battery post to starter and then comes to negative post through a frame? Many car books usually state that it is the positive wire that gives power to the starter and not vice versa? Where is the flaw in this reasoning - it is certainly how electricity used in cars today practically, not theoretically? I started reading about Ben Franklin and then "real" flow of electrons and really got lost because i understand that usually it does not matter in simple circuits which way it goes to make it work but I still wanna get a little bit closer to my understanding: does this dc current (force, what ever you wanna call it) works in a car - a. travels from positive to negative b. from negative through a frame, starter and into positive c. people don't really know at this time so don't bother :)
UPDATE: Thank you for the answers and adding to this discussion - Franklin was probably wrong but car manufacturers of 21st century certainly have all the knowledge they need yet the THICK positive cable connects to the starter but probably thick cable connects from starter to frame as well and frame is pretty thick itself :) - it is just interesting to know that there are several circuits using the frame as the path, possibly at the same time - I'll have to read more on that : as far as "electron flow" i read that it may take 1 electron from negative post 4 HOURS to reach positive post so I'm not sure what kind of "flow" we are talking about and if the power that makes gadgets work is indeed the "flow" rather than some "force" or "field" that is instantly present once you close the circuit. I also read that change of frame polarity (positive or negative cable to the car frame) which happened sometime in the 1950s was to better deal with higher voltage systems (change from 6v to 12v) and rusting of car frame and bodies due to electrical current running through the frame. How did switch from positive wire to frame to negative wire to frame help with rusting ? - I still have to do more research to see if it was indeed one of the reasons to switch frame wires and whether it did any good but it seems that manufacturers' thoughts about the way current traveled through the frame certainly shaped their decision to make the change