The first explorers had very little to help them find their way around the world. Travelers used simple maps and learned how to find their way, or navigate, using the sun and the stars.
During the day, travelers can always find out where east and west are, because the sun rises in the east and sets in the west.
At night, they can use the stars to find out where north and south are.
An imaginary line called the equator circles the world halfway between the North and South poles.
In countries north of the equator, the North Star shows which way is north.
A pattern of bright stars called the Big Dipper points to Polaris, the North Star.
In countries south of the equator, the upright line in a group of stars called the Southern Cross points to the south.
When was the Compass Invented?
In the 11th century, a Chinese scientist called Shen Kua made a magnetic compass.
He held up a thread of silk attached to the center of a needle and watched the needle point to the south.
When he rubbed the needle with a loadstone, it pointed to the north.
About 100 years later, sailors began to use magnetic compasses to find their way across the oceans.
Three or four hundred years ago, most ships carried a piece of loadstone that sailors used to magnetize their compass needles. Loadstone, also spelled lodestone, is a hard black magnetic rock.
A long piece of this rock would point north / south if hung by a string.
Hikers and sailors still use magnetic compasses to tell directions. Small boats made of wood or fiberglass use a magnetic compass called a mariner’s or maritime compass. It consists of a ring-shaped magnet attached to a card. The points of the compass are marked on the card.
The card and magnet float in a bowl of water mixed with alcohol. The compass always floats horizontally, so that it can work properly even in stormy seas.
Magnetic compasses don’t work properly near steel or electrical machines. So modern ships use a special compass called a gyrocompass.
Gyrocompasses do not use magnetism and can be set to point towards the geographic North Pole.