Battery

Paper Clip

Coiled wire, resting in curve of paper clip

End of wire with one side stripped of coating (not to scale)

Disk Magnet

Side View Front View

Andercell

From here, we’ll just show the paperclip and the coil of wire, and the magnet below

1: The disk magnet has a permanent North and South

N

S

3: Once the circuit is complete, the current through the coil creates a magnetic field through the center of the coil

4: This magnetic field has its own North and South poles

N S

5: What happens when the electromagnet coil feels the magnetic force of the disk magnet?

2: The shaved part of the wire completes the electrical connection to the battery

N

S

N S

1: The South pole of the coil-magnet is attracted to the North pole of the disk magnet, and the coil begins to rotate

Repels Attracts

N

S

N

S

1: The bare wire is still connected to the paperclip, so the circuit is still complete. Thus, the coil is still a magnet, pulling in line with the disk magnet

N

S

1: Now that the coil has rotated this far, the coating on the wire cuts off the electricity. No current flows, so the coil is no longer an electromagnet

2: The coil has inertia, so it keeps spinning

N

S

1: Inertia keeps it spinning while the coating is still preventing the circuit from being complete

N

S

1: Inertia keeps it spinning while the coating is still preventing the circuit from being complete

N

S

1: Inertia keeps it spinning while the coating is still preventing the circuit from being complete

N

S

1: Inertia keeps it spinning while the coating is still preventing the circuit from being complete

Until…

N

S

1: The shaved side of the wire has again come into contact with the paper clips, closing the circuit.

The loop is an electromagnet again!

2: The current in the wire creates a magnetic field again, which feels the force of the disk magnet, and the whole thing starts again.

N

S