Positive charge moves from higher potential to lower potential, so in a wire, current always flows "downhill"; and the steeper the slope (that is, the greater potential difference between the ends of the wire), the larger the current will be:
$$I=G\Dl V$$
where \(G\) is called the conductance. Conductance measures how easy it is for current to flow: the larger the conductance, the greater the current will be for a given potential difference. For a wire, the conductance can be found from the formula
$$G=\sigma \frac{A}{L}$$
Something to calculate conductance, how does conductivity change, what is the current through the wire.