A compass points north because the Earth is a magnet. The Earth’s magnetic field is generated by the movement of molten iron in the outer core. The magnetic field lines of the Earth run from the south magnetic pole to the north magnetic pole. The north pole of a compass magnet is attracted to the south magnetic pole of the Earth, so the compass needle points north.

The Earth’s magnetic poles are not located at the same places as the Earth’s geographic poles. The Earth’s magnetic north pole is currently located in northern Canada, while the Earth’s geographic north pole is located in the Arctic Ocean. This is why a compass needle does not point directly to the geographic north pole.

The Earth’s magnetic field is also not perfectly symmetrical. The magnetic field lines are stronger near the magnetic poles and weaker near the equator. This is why a compass needle may not point perfectly north at all locations on Earth.

The Earth’s magnetic field is constantly changing. The magnetic poles are slowly drifting, and the strength of the magnetic field is also changing. This is why a compass needle may not always point in the same direction over time.

Despite these changes, a compass is still a reliable way to find north. The Earth’s magnetic field is strong enough to overcome the effects of gravity and other forces, so the compass needle will always point in the direction of the Earth’s magnetic north pole.

The direction of zero on a compass is called the magnetic declination. The magnetic declination is the angle between the direction of true north and the direction of magnetic north. The magnetic declination varies from place to place. In the United States, the magnetic declination is generally positive, which means that the magnetic north pole is located east of true north. The magnetic declination is zero along the agonic line, which is the line that passes through points where the magnetic north pole and true north are aligned.

You can find the magnetic declination for your location by using a compass or by looking at a map. It is important to take the magnetic declination into account when using a compass to navigate.