Fleming's left hand rule
Fleming's left hand rule is used when electricity or electrical current is already being passed along a wire.
LEFT = ELECTRICITY
When a current flows through a wire and the wire is passed through a magnetic field, Fleming's left hand rule can tell you the direction in which force is applied to the wire.
NOTE: Carbon is used as the rod because if steel was used it would stick to the magnet.
Carbon is non magnetic but because carbon can carry an electrical current a magnetic field is formed around the carbon rod when the current flows. The two magnetic fields interact and forces occur.