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2000 years ago, the Greeks thought that the Earth was a perfect sphere - Earth actually bulges out around the
equator and is slightly squashed at the poles
Greek mathematician, calculated the Earth's circumference using geometry and observation of the sun - his estimation was off only 6,250 km, an error of 15%
A fixed place on the Earth's surface from which direction & location can be described
also used as a refernce point when describing location on earth - a circle halfway between the poles that divides the Earth into the Northern and Southern Hemispheres
One way to determine North which uses the natural magnetism of the Earth to indicat direction
Geographic poles and Magnetic poles (have changed location throughout history)
The Earth has two different sets of poles
Difference between geographic north and magnetic north
When using a compass to map or explore the Earth's surface, you need to make correction for the
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