In a bar magnet, unlike poles attract each other. This means that the north pole of one magnet is drawn toward the south pole of another magnet. This fundamental behavior is due to the magnetic field lines, which flow from the north pole to the south pole. When unlike poles are brought near each other, their magnetic field lines connect smoothly, creating an attractive force. Conversely, like poles repel each other because their magnetic field lines oppose and create a repulsive force. This attraction and repulsion principle explains how magnets interact and is why opposite poles come together while similar poles push apart.