The Earth's Magnetic Field - Answers

A1.Those of a simple bar magnet.

A2.The Earth rotates around an imaginary line that joins the 'true north' and 'true south' poles.

A3.The geographical meridian

A4.The magnetic meridian.

A5.The magnetic declination.

A6. It is thought to be due to the movement of the charged particles in the liquid core.

A7. Rocks formed from the molten state contain indicators of the magnetic field at the time of their solidification. The study of such "magnetic fossils" indicates that the Earth's magnetic field reverses itself every million years or so (the north and south magnetic poles switch).

A8. If a piece of magnetised iron is suspended freely (hung from a fine thread or 'floated' on a pivot) it aligns itself with the field lines from the Earth's core.

A9.The 'north' poles on compasses sought out the magnetic north whether or not there was cloud cover. So they were called north poles.

A10. A south pole.