Why dont magnets around earth fly towards the earths magnetic poles?

In summary, the Earth's weak magnetic field at its surface (around microteslas) is not strong enough to pull a magnet to its poles. The magnetic field at the Earth's core is substantial, but due to the distance of 6400km, it is not a significant force. The force between two magnets depends on their strength, but the Earth's magnetic field does not change based on the object it is acting on. The Earth's magnetic field is caused by the motion of free electrons in the core, similar to how electrostatic charge creates a coulomb force. The north and south poles of magnets attract each other due to the arrangement of free electrons in a metal object. All metals have free electrons, not just magnetic ones
  • #1
mapa
29
0
Why don't magnets fly to Earth's magnetic poles? I understand that Earth's magnetic pull must be strong enough to pull a magnet to the pole, but what is the force required for a magnet to get pulled the over their? How does one calculate whether a magnetic field is strong enough in order for two magnets to pull into each other?
 
Physics news on Phys.org
  • #2
At the surface of the Earth the magnetic field is very weak, in the region of microteslas. A strong lab magnet is about 10 teslas for comparison. We can walk past most labs without having metal object snatched from our hands afterall! The magnetic field at the Earth's core is substantial, but remember that we are about 6400km away from it!
 
  • #3
On a compass there is a force pulling on its magnetic poles. What is the force of the Earth magnetic force acting on a small compass? How strong does the Earth's poles need to be in order to pull on a magnet?
 
  • #4
Same force, order of microteslas, compass needles are very light so are easily moved.

The Earth and the magnet pull on each other. The Earth's magnetic field pulls on all magnets.

I suppose its a bit like asking why a westerly wind doesn't blow all the cars into the ocean, since it does for feathers.

Are you simply asking what is the force between two magnets of of known strength?
 
  • #5
Well I was looking for the strength of the Earth's magnetic field acting on an object.
 
  • #6
The strength of the Earth's magnetic field isn't something that depends on the thing you're testing it with. The forces and accelerations due to the Earth's magnetic field change though [pedantic language point].

I really don't understand magnetism, despite knowing enough mathematics to model quite a lot of phenomena caused by it.

Where does the magnetic force come from? Or how do we predict it?

F=qvXB I know, but what are the q's and v's in a paper clip that gets stuck to a magnet?
(Free electrons?)

For the electrostatic charge, we can say "Right, this thing is + and that thing is -, so they should both experience a coulomb force towards each other". Norths attract souths is the analogue, but both also attract paper clips.
What's that about?

Where does "norths attract souths" appear in the equations anyway? What is a north pole?
(I seem to remember, once had a problem on a sheet that asked to prove that a magnetic dipole is like a tiny circuit loop...but I never did it and don't remember the answer x.x)
 
  • #7
I could be wrong here but about the paper clip thing.

There are free electrons in the paper clip, when put at a positive pole, the electrons are attracted towards it holding onto it.

When put at a negative pole the electrons are pushed to the far side of the paperclip, giving the side closest to the pole a 'positive' value, therefore attracting again.
 
  • #8
I thought all metals had free electrons though, not just magnetic ones (of which there are fairly few I think? Fe, Ni, Co? God, school feels so long ago)
 
  • #9
If you drop a magnet a couple times will it land one way or the other over and over?
 

1. Why don't magnets around Earth fly towards the Earth's magnetic poles?

Magnets around Earth do not fly towards the Earth's magnetic poles because of the Earth's magnetic field. The Earth's magnetic field is created by the movement of molten iron in the Earth's outer core. This magnetic field exerts a force on magnets, pulling them towards the Earth's geographic North and South poles. This force is strongest at the poles, which is why compass needles point towards them.

2. How does the Earth's magnetic field affect magnets around Earth?

The Earth's magnetic field affects magnets around Earth by exerting a force on them. This force causes magnets to align themselves with the Earth's magnetic field, with the North pole of the magnet pointing towards the Earth's geographic North pole and the South pole of the magnet pointing towards the Earth's geographic South pole. This is why magnets do not fly towards the Earth's magnetic poles, but instead align with them.

3. Can magnets around Earth ever fly towards the Earth's magnetic poles?

No, magnets around Earth cannot fly towards the Earth's magnetic poles. The Earth's magnetic field is constantly active and will continue to exert a force on magnets, pulling them towards the Earth's geographic poles. Unless the Earth's magnetic field were to significantly weaken or change, magnets will always align with the Earth's magnetic field.

4. Are the Earth's magnetic poles the same as the Earth's geographic poles?

No, the Earth's magnetic poles are not the same as the Earth's geographic poles. The Earth's geographic North and South poles are the points where the Earth's axis of rotation intersects the Earth's surface. The Earth's magnetic poles, on the other hand, are the points where the Earth's magnetic field is strongest and vertical. These points are not fixed and can change over time.

5. What would happen if the Earth's magnetic field were to disappear?

If the Earth's magnetic field were to disappear, magnets around Earth would no longer experience a force pulling them towards the Earth's magnetic poles. This means that magnets would not align with the Earth's magnetic field and could potentially move freely. However, the disappearance of the Earth's magnetic field would have much larger consequences, such as leaving the Earth vulnerable to harmful solar radiation and disrupting animal migration patterns.

Similar threads

Replies
32
Views
1K
  • Electromagnetism
Replies
11
Views
1K
  • Electromagnetism
Replies
7
Views
1K
  • Electromagnetism
Replies
2
Views
891
Replies
6
Views
751
  • Electromagnetism
Replies
4
Views
9K
Replies
4
Views
275
Replies
8
Views
2K
Replies
5
Views
1K
Replies
2
Views
1K
Back
Top