Question

1. Why do electrons (blue dots) move? The flow of current (+) is opposite to the flow of the electrons. ; note if toward or away from + terminal of the battery.

2. What does the Ammeter (on the left) measure? How is this shown in thesim?

3. What role do the ?green dots? in the resistor play in the sim? What do you think they represent? What does this tell you about the effect of resistors in a circuit?

Answer 1

The electrons move because they experience an electromotive force in the wire. The battery sets up an electric field and the electrons experience a force due to the field. The flow of current is opposite the direction of electron flow due to convention only.

The ammeter measures the current: counting the number of electrons that pass a given point per second.

The green dots serve to perturb the flow of electrons. They stop the electrons from moving in a perfectly straight path. They represent other atoms in the resistor. This tells you that a resistor inhibits the flow of charge.

The sim, as screenshot, has a few things wrong worth mentioning: the charge does not "build up" in the wire as you see to the right-hand side. The current in the series circuit flows evenly throughout. It also looks like the electrons follow a straight path across the resistor, perhaps the simulation shows them slowing down as they cross the the green dots; this would be incorrect. The electrons across the entire circuit will slow down then. The resistor has an effect on the entire circuit since it effects some electrons, which of course interact with all the other electrons via Coulomb force.