Friday, October 1, 2010

Compasses in the southern hemisphere?

In geography we were learning about the earth's magnetic field and how it causes the compass needle to always point north. We wondered if in the southern hemisphere the needle would also point north, or if it would instead point south, as the South Pole is closer in that part of the world?

17 comments:

  1. Ellie says that the compass needle always points north and Meabh says that it points south in the southern hemisphere. Which of them is right??!!

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  2. The compass needle points south in the sourthern hemisphere and north in the northern hemisphere

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  3. You are right in one way, but there is another element to this that nobody in the class has yet discovered. Go to Google and search "compass in the southern hemisphere" and see if you can find out anything else.

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  4. in north they point to the north magntic pole and in south they point to the south magnetic field

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  5. it points at the south magnetic pole

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  6. This is true, but the needle still points north. Why??

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  7. because there is a white and red needle and one points south and one pionts north

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  8. the neddle points both north and south

    in the south it points to the south magnetic pole (in antartica)
    in the north it points to the north magnetic pole
    (in the arctic)

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  9. In the northern hemisphere the compass points north and points south in the southern hemisphere

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  10. the compass needle points to the north magnetic pole in the northern hemisphere and to the south magnetic pole in southern hemisphere.

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  11. We know that the needle points north in the southern hemisphere, but as yet nobody has found out WHY. If someone can get the correct answer by Friday I'll give them €20(classroom money!) but otherwise I'll be telling you myself.

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  12. the needle points north-it does anywhere in the world- this is because there are two types of magnets. they are north pole magnets and south pole magnets. the north pole magnets attract the south pole ones and the other way round. the magnet in the compass is a south pole magnet and it aligns itself with the natural magnetic field of the earth.

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  13. VERY CLOSE! I'll reveal the answer on Fri if no-one else gets it before then.

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  14. It's all down to Pole Magnetism. In short because the earth is magentic and the needle of a compass is also. 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. 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.

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  15. Here's what I found out on the internet:
    "An interesting detail is that there are northern-hemisphere and southern-hemisphere compasses. This is due to the fact that the magnetic field lines to which a compass needle aligns point into the earth at the north and south magnetic poles. This means that in the northern hemisphere, the north end of the needle is pulled downwards and so the south end is counter-weighted to balance the needle. Therefore, when you use a northern hemisphere compass in, say Australia, the south end of the magnet is pulled downwards by the magnetic field and is also heavier than the north end - resulting in a needle that catches and drags on the bottom of the compass housing when the compass is held horizontal."

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  16. does anybody get the 20 killies?

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