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iseason
Hi Guys

I was wondering how strong the pull north on compass needles was. Is this a variable scale?

Would a very large compass be different? I know the needle receives this property via charging from a coil. Does larger charge equal stronger,longer attraction or is the earths pole the governor no matter what the compass is like.
When the needle is prevented from pointing north is there a cost to the compass (magnetic charge).

Cheers
Iseason

Lasand
Not quite sure I understand your questions.

A compass needle is a permanent magnet. It will line up parallel with the earth's magnetic field's lines of force. It isn't so much that the north magnetic pole "pulls" on it.

The bigger the compass the slower it is to turn, too big and the friction might be too much for it to turn.

The earth's magnetic field varies from 30 microteslas to 60 microteslas.

The compass needle shouldn't lose it's magnetism as long as you don't hit it or heat it up too much.

Don't understand your use of the word charge relating to magnets.

If you line up a straight wire conductor and the compass needle with the earth's magnetic field a current of .1 to .2 amperes won't affect the needle much. When you get the current up to 3 amps. and more the needle can deflect up to 90 degrees from magnetic north.
WhiteRhasta
Well the compass needle is actually magnetic. The Earth is what draws the compass/needle to the direction of which you are traveling. It reacts because the Earth itself is similar to a magnet, it contains magnetic fields. Magnetic poles from North to South.

It really doesn't so much as to relate to the compasses pull depending on size variations. The strength of the magnet inside is far more than the Earth's magnetic fields.

Also depending on location do you run into deviations, commonly attributed on ships/boats.

iseason
Hi Guys.

I actually was a bit lazy here and didn't even google for a start off (as I should have).

the question is related to energy. If I increase the size of my compass needle (or the charge which initiates the behavior) does this affect the "pull". I think the answer has come back as no.

But if I link a series of com pas needles , does the "pull" remain constant (in a fixed location)...What would happen if I were to alternate two needles?......Let's say the poles are changed as soon as it hits north... can I do that?

cheers
Iseason
Lasand
Don't know if I would want a "strong" magnet as a compass. The needle would start pointing toward large masses like the furnace, fridge, and such, and not always the "red end "would point to them.

A couple of my "experiments" were affected by things around the house turning the needle out of line with magnetic north.

You can put two or three compassses in line and they will all point to the north.

If you could magically reverse the magnetism then the plain end of the needle would swing around and point north instead of the red end.
Lasand
I just put three cheap compasses in a north-south line and they looked OK.

When I put the same compasses side by side in an east-west row the needles ended up pointing northwest and took a while to settle down.

I'll let someone else explain that.

Enough for now.
AlexG
QUOTE (Lasand+Feb 4 2009, 05:29 PM)
I just put three cheap compasses in a north-south line and they looked OK.

When I put the same compasses side by side in an east-west row the needles ended up pointing northwest and took a while to settle down.

I'll let someone else explain that.

Enough for now.

The compass needles are magnets. When you put them in a row north to south, they line up with the earth's magnetic field AND the north and south poles of each compass needle lines up as well.

When you put them side by side east to west, you are lining up the same poles side by side, so the needles influence each other.
Lasand
Keep in mind these are cheap things, less than two dollars each.

An interesting thing is that the two outer compasses both point to the northwest, but the compass in the center points due west. Why west?
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