Demos to Prepare:
Oersted's Discovery.
Left-Hand Rules:
For Coils.
For Wires
The Big Magnet.
The Big Coil..
Great Relays.
Lock-in Relays.
Exciting Soleniods.
The Western Telegraph.
Electric Meters.
Here is a summary of Flemming's rules. For a complete discussion with diagrams, please visit the awesome King of Physics website.
Magnetic Field Around a Conductor:
In a current carrying conductor, the lines of force are circles
perpendicular to the conductor.
Left Hand Rule for a Field Around a Wire:
For Wires: Mentally grasp the wire with the left hand with thumb pointing
in the direction of the electron flow (- to +) and the fingers
will show the direction of the magnetic field (N to S).
Magnetic Field Around a Coil:
For Coils: Mentally grasp the coil with the left hand with fingers in the direction
of the electron flow and the thumb will point to the N pole.
Coils and Solenoids:
The strength of an electromagnet is proportional to the number of ampere•turns.
An iron core concentrates the field.
Powerful Electromagnets save our hero. Video:
