Final answer:
Magnetic declination refers to the difference between true north and magnetic north, which are not located at the same spot on Earth. A compass points to magnetic north, which is the effective south pole of a bar magnet and can alternatively be called the geographic north.
Step-by-step explanation:
The difference between true north and magnetic north is known as magnetic declination. These two points are not located at the same spot on the Earth. True north, also called geographic north, is the direction along the Earth's surface towards the geographic North Pole. Magnetic north, on the other hand, is the direction that a compass needle points to as it aligns with the Earth's magnetic field, which is generated by flowing liquid metals in the outer core of the Earth. Interestingly, the magnetic north is in constant motion due to changes in the Earth's magnetic field. Furthermore, what a compass reads as the magnetic north pole is effectively the south pole of a massive bar magnet, because magnetic field lines travel from the magnetic north to the magnetic south pole.