What repels two magnets?

The ability of magnets to attract objects and each other is fascinating, but their capacity to repel is equally fundamental and powerful. Repulsion—the invisible push—is a direct consequence of the physics governing magnetic fields. Understanding what causes this force is key to utilizing magnets effectively, whether in toys, motors, or advanced levitation technology.

The Foundation of Repulsion: Magnetic Polarity

The simple and definitive answer to "What repels two magnets?" lies in the concept of magnetic polarity. Every magnet, regardless of its shape or size, has two distinct ends or poles: a North (N) pole and a South (S) pole.

The universal law of magnetism dictates the interaction between these poles:

Like Poles Repel: When the North pole of one magnet is brought near the North pole of another, a repulsive force is generated. The same is true when two South poles are brought together. The magnetic field lines push against each other, creating the resistance you feel when trying to force them together.

Opposite Poles Attract: When a North pole and a South pole are brought near each other, the magnetic field lines merge, creating an attractive pull.

The Mechanism of the Repulsive Force

Repulsion is not just a theoretical concept; it's a physical force governed by the magnetic field lines that surround every magnet.

1. Field Interference: The magnetic field lines always originate at the North pole and loop around to enter the South pole. When you attempt to push two like poles together (e.g., North-to-North), the field lines emanating from each magnet are running in opposing directions and are forced to compress and deform.

2. Pressure Buildup: This compression creates a high-pressure zone of magnetic energy between the two surfaces. The magnets essentially resist the distortion of their fields, resulting in a physical push that attempts to restore the equilibrium of the field lines. This is the repulsive force you experience.

Real-World Applications of Magnetic Repulsion

While attraction is used for holding things together, the unique characteristics of repulsion are essential for many modern inventions:

Maglev Trains: Perhaps the most dramatic use of repulsion. These trains use powerful, superconductive magnets to lift the train car off the track (levitation) and propel it forward. By eliminating friction with the ground, these trains can achieve incredible speeds.

Magnetic Bearings: In high-speed machinery like industrial turbines, magnetic bearings use repulsion to hold a rotating shaft in place without any physical contact. This eliminates friction and wear, allowing the machines to operate faster, quieter, and for longer periods without maintenance.

Simple Dampers and Springs: Magnets can be used in certain devices as non-contact springs or dampers. The repulsive force acts as a cushion, absorbing shock or maintaining a precise, contactless gap between components.

In essence, the repulsion of two magnets is a perfect demonstration of the invisible force of nature following its strictest rule: like poles cannot coexist in close proximity and will push each other away with a strength that is inversely proportional to the square of the distance between them.