# How is current used, say, in a light bulb?

I understand that current is the flow of charge, not necessarily of electrons (which drift slowly). The way I imagine this is a long tube filled with balls that just fit within the tube - when you push a ball at one end of the tube, the ball at the other end is pushed basically instantly, even though none of the balls move particularly much.

A filament light bulb works because a piece of wire with high resistance heats up and causes light to be seen. In the ball-in-tube analogy, I guess this would be like having three tubes connected to each other - one full of air, one full of oil and another full of air. All would hypothetically be connected to each other (pretend the water had no way of filling into the air tubes).

Essentially:

[air][water][air] = [wire][light bulb][wire]


I don't understand how moving one electron and essentially causing charge to be propagated throughout the circuit can cause a filament light bulb to work.

Can someone explain this using the ball-in-tube analogy, or if I have some conceptual misunderstanding in the analogy, correct me?

• Initially your tube was full of balls and now air also why did you chose water/oil in analogous to bulb I don't get the reason – Utkarsh futous Apr 5 '17 at 7:08
• @Utkarshfutous Because the filament has increased resistance, so I assume that would be analogous to a ball in oil, which is more viscous than air. – sidney Apr 5 '17 at 12:53