Objective
Grow the circular magnetic field around a current-carrying wire and watch tiny compass needles align to it, following the right-hand rule.
The idea
Electric current makes magnetism. The field curls in circles around the wire, and its direction depends on which way the current flows - the right-hand rule in action.
Try this
- 1Slide the current up and watch the compass needles swing into rings.
- 2Flip the current direction and watch every needle flip too.
- 3Move the probe around the wire and read the field strength.
- 4Note how needles near the wire are strongest.
Watch for
- Field lines are closed circles - no monopoles in magnetism.
- Field direction follows the right-hand rule around the current.
- Field strength grows with current and falls with distance.
- Compass needles always align along the field direction.