How does a compass work? Does it always point North?

Question

Someone please explain in simple terms. thanks.

Answer 1

It works via magnetic force, this should explain it more

http://en.wikipedia.org/wiki/Magnetic_fo...

Answer 2

The needle points towards the strongest magnetic force, which is the North pole.  if you put a magnet on a compass, you will find it points toward the magnet and follows its every move.

Answer 3

The needle always points to the North so if you wish to go to the east you have to go the the Right(90 Degrees) of the direction the needle is pointing and so forth for all other directions.

Answer 4

Let me put it in a simple form, since others have used long explainations or links with incomplete answers.

A compass workes on a principle of magnetism.  The strongest points of magnetism on our planet are the north and south poles (pole meaning magnetic focual point).  The north pole is the stronger.

What is concidered true north and the north "pole" are not the same.  As others have pointed out, wikipedia will give you the difference between true north and the North pole.

A compass has a lodestone (magnetic stone) placed in the tip of the needle or actual needle itself.  This stone is attracted to the strongest pole and will always point to it.

Answer 5

No matter where you stand on Earth, you can hold a compass in your hand and it will point toward the North Pole. What an unbelievably neat and amazing thing! Imagine that you are in the middle of the ocean, and you are looking all around you in every direction and all you can see is water, and it is overcast so you cannot see the sun... How in the world would you know which way to go unless you had a compass to tell you which way is "up"? Long before GPS satellites and other high-tech navigational aids, the compass gave humans an easy and inexpensive way to orient themselves.

But what makes a compass work the way it does? And why is it useful for detecting small magnetic fields, as we saw in How Electromagnets Work? In this article, we will answer all of these questions, and we'll also see how to create a compass from scratch!

A compass is an extremely simple device. A magnetic compass (as opposed to a gyroscopic compass) consists of a small, lightweight magnet balanced on a nearly frictionless pivot point. The magnet is generally called a needle. One end of the needle is often marked "N," for north, or colored in some way to indicate that it points toward north. On the surface, that's all there is to a compass.

The reason why a compass works is more interesting. It turns out that you can think of the Earth as having a gigantic bar magnet buried inside. In order for the north end of the compass to point toward the North Pole, you have to assume that the buried bar magnet has its south end at the North Pole, as shown in the diagram at the right. If you think of the world this way, then you can see that the normal "opposites attract" rule of magnets would cause the north end of the compass needle to point toward the south end of the buried bar magnet. So the compass points toward the North Pole.



To be completely accurate, the bar magnet does not run exactly along the Earth's rotational axis. It is skewed slightly off center. This skew is called the declination, and most good maps indicate what the declination is in different areas (since it changes a little depending on where you are on the planet).

The magnetic field of the Earth is fairly weak on the surface. After all, the planet Earth is almost 8,000 miles in diameter, so the magnetic field has to travel a long way to affect your compass. That is why a compass needs to have a lightweight magnet and a frictionless bearing. Otherwise, there just isn't enough strength in the Earth's magnetic field to turn the needle.



The "big bar magnet buried in the core" analogy works to explain why the Earth has a magnetic field, but obviously that is not what is really happening. So what is really happening?

No one knows for sure, but there is a working theory currently making the rounds. As seen on the above, the Earth's core is thought to consist largely of molten iron (red). But at the very core, the pressure is so great that this superhot iron crystallizes into a solid. Convection caused by heat radiating from the core, along with the rotation of the Earth, causes the liquid iron to move in a rotational pattern. It is believed that these rotational forces in the liquid iron layer lead to weak magnetic forces around the axis of spin.

It turns out that because the Earth's magnetic field is so weak, a compass is nothing but a detector for very slight magnetic fields created by anything. That is why we can use a compass to detect the small magnetic field produced by a wire carrying a current

Answer 6

I would add that the compass will point to 'magnetic north', rather than 'true north' (i.e. the North pole).  The difference is about 5 degreed or so in the U.K, but if you are planning on an Arctic Expedition, it's something you ought to remember.

Answer 7

it points  to magnetic north not true north , the magnetic north actually  moves from year to year and most times if you have a compass pointing to magnetic north,

true north is about 6 degrees to the west IE 354degrees on a compass

a compass works by following the lines of the magnetic field of the earth( the planet not the soil) it will allways point north south because the pointer has been magnetised and has the same magnetic field as the planet there for follows the same pattern

just google magnetic north or compass or even magnets  i am sure you will find lots more answers there for you and diagrams  hope this helps

ps it allways points  south aswell (just think about it lol)