Which end of the compass needle will point toward the north pole of a bar magnet?
The black rectangle represents a bar magnet. The magnet's North and South poles are labeled. The other item represents a compass; the red end of the needle is the end that would point towards Earth's North Magnetic Pole. Notice that the red end of the compass needle points toward the south pole of the magnet.
But the magnet is the opposite way around to how you might think, with its south pole up near Earth's actual (geographic) north pole and vice-versa. A compass needle points north because the north pole of the magnet inside it is attracted to the south pole of Earth's built-in magnet.
- The Earth is a magnet that can interact with other magnets in this way, so the north end of a compass magnet is drawn to align with the Earth's magnetic field. Because the Earth's magnetic North Pole attracts the "north" ends of other magnets, it is technically the "South Pole" of our planet's magnetic field.
- A magnetic compass does not point to the geographic north pole. A magnetic compass points to the earth's magnetic poles, which are not the same as earth's geographic poles. Furthermore, the magnetic pole near earth's geographic north pole is actually the south magnetic pole. When it comes to magnets, opposites attract.
- The Magnetic North Pole (also known as the North Dip Pole) is a point on Ellesmere Island in Northern Canada where the northern lines of attraction enter the Earth. A compass needle rests freely in its casing so it can maneuver itself. When you pull out a compass, it aligns itself with the Earth's magnetic field.
At the north pole, for example, if you hold the compass horizontally the needle which is supposed to point north will point south, toward the north magnetic pole. That's not saying much, since at the north pole ANY horizontal direction is south.
- If you are within the magnetic field of the Earth (which extends about one fourth the way to the Moon) or other magnetized body, yes the regular compass will work. Outside of this, the magnetic field away from the Sun and some of the other planets is probably too small to move the needle on a regular compass.
- "If you look at the north pole of the bar magnet you have the field lines going from the north pole to the south pole, but for the earth it's exactly opposite," Maus explains. So the north magnetic pole is where the earth's magnetic field lines pull toward the planet, acting like the south pole of a bar magnet.
- Magnetic declination or variation is the angle on the horizontal plane between magnetic north (the direction the north end of a compass needle points, corresponding to the direction of the Earth's magnetic field lines) and true north (the direction along a meridian towards the geographic North Pole).
The needle of a magnetic compass must be made of a metallic substance, which can be magnetized for an extended period of time. The most common substance used for compass needles is steel. Steel is an alloy of iron and a small amount of carbon.
- The magnetic compass was an important advance in navigation because it allowed mariners to determine their direction even if clouds obscured their usual astronomical cues such as the North Star. It uses a magnetic needle that can turn freely so that it always points to the north pole of the Earth's magnetic field.
- Say it is two o'clock, draw an imaginary line between the hour hand and twelve o'clock to create the north-south line. You know the sun rises in the east and sets in the west so this will tell you which way is north and which way south. If you are in the Southern Hemisphere then it will be the other way round.
- Moving point charges, such as electrons, produce complicated but well known magnetic fields that depend on the charge, velocity, and acceleration of the particles. Magnetic field lines form in concentric circles around a cylindrical current-carrying conductor, such as a length of wire.
Updated: 4th November 2019