What an electric current is
The neon bulb activity earns the definition the rest of the chapter is built on.
Electric current
A current of electric charges flowing through a conductor is called an electric current.
Two things the definition requires
Read it carefully and it names two conditions, both of which the activity satisfied.
Charges
There must be electric charges to move. The rubbing supplied them.
A conductor
There must be something for them to flow through. The wire supplied that.
Where you have met this before
Chapter 10 said the same thing from the other direction, when testing which substances conduct: a current is a flow of charge, and it needs charged particles that are free to move. This chapter now asks how many charges flow, how hard they are pushed, and what holds them back.
A current is charge on the move
An electric current is flowing electric charge. Everything else in this chapter — the ampere, the volt, the ohm — is a way of putting a number on that flow.