Earth's Magnetism

Earth as a Giant Magnet

Our magnetic planet.

Earth behaves like a giant bar magnet buried at its center. Its magnetic field is generated by swirling currents of liquid iron and nickel in the outer core.
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Key Points

  1. Earth's magnetic South pole lies near its geographic North pole.
  2. Earth's magnetic North pole lies near its geographic South pole.
  3. Causes a compass needle's North pole to point toward the North.
  4. Forms a protective shield (magnetosphere) against solar wind.

Olympiad Fact

Earth's magnetic poles are not fixed—they shift slightly every year in a natural process called 'polar drift'.

The Magnetic Compass

Nature's GPS.

A magnetic compass is a navigation instrument with a small magnetized needle balanced on a pivot. It rotates freely to align with Earth's magnetic field.
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Key Points

  1. The needle is a tiny magnet that always rests North-South.
  2. The North-pointing tip is usually painted red for easy reading.
  3. Its outer case is made of non-magnetic aluminum, brass, or plastic.
  4. Used by sailors, pilots, and trekkers to find directions.

Olympiad Fact

A compass gives false readings if placed near iron or steel objects because the metal diverts Earth's magnetic field.

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