One of the characteristic compasses of that time was a south-pointing ladle whose handle pointed south. Only in 11th century, compass is used for navigation, first on land and then on water. First compasses were made of lodestone but later a magnetized steel needle is used as a main part of a compass.
Naval compasses of China were made in the form of a magnetic needle that floated in a bowl of water which allowed for the needle to stay in horizontal position, especially at the rough sea. Somewhere between 12th and 13th century, compass arrived in Europe in both dry and floating forms.
It prolonged sailing season, which was earlier between October and April and relied on the clear skies, to the whole year which in turn resulted in a gradual, but sustained increase in shipping movement. Compass appeared in Islam world in 13th century.
It is one of the most important instrument s for navigation. Magnetic compasses are the most well known type of compass. While the design and construction of this type of compass has changed significant ly over the centuries, the concept of how it works has remained the same. Magnetic compasses consist of a magnetized needle that is allowed to rotate so it lines up with the Earth's magnetic field.
The ends point to what are known as magnetic north and magnetic south. Ancient Greeks understood magnetism. As early as 2, years ago, Chinese scientists may have known that rubbing an iron bar such as a needle with a naturally occurring magnet , called a lodestone , would temporarily magnetize the needle so that it would point north and south. Very early compasses were made of a magnetized needle attached to a piece of wood or cork that floated freely in a dish of water. As the needle would settle, the marked end would point toward magnetic north.
As engineer s and scientists learned more about magnetism, the compass needle was mounted and placed in the middle of a card that showed the cardinal direction s—north, south, east, and west. A spearhead and the letter T, which stood for the Latin name of the North Wind, Tramontana , signified north.
This combination evolve d into a fleur-de-lis design, which can still be seen today. All 32 points of direction were eventually added to the compass card. Historians think China may have been the first civilization to develop a magnetic compass that could be used for navigation. Chinese scientists may have developed navigational compasses as early as the 11th or 12th century.
Western Europeans soon followed at the end of the 12th century. In their earliest use, compasses were likely used as backups for when the sun, stars, or other landmark s could not be seen. Eventually, as compasses became more reliable and more explorers understood how to read them, the devices became a critical navigational tool.
This discrepancy between magnetic north and true north is called variation by mariner s or pilot s or magnetic declination by land navigators and varies depending on location. Variation is not significant when using magnetic compasses near the Equator , but closer to the North and South Poles, the difference is much greater and can lead someone many kilometers off-course. Navigators must adjust their compass readings to account for variation. Other adaptation s have been made to magnetic compasses over time, especially for their use in marine navigation.
When ships evolved from being made of wood to being made of iron and steel , the magnetism of the ship affected compass readings. This difference is called deviation.
Adjustments such as placing soft iron balls called Kelvin sphere s and bar magnets called Flinders bar s near the compass helped increase the accuracy of the readings. Fashioned into the shape of a spoon or ladle, the lodestone sat upon a flat, square-shaped plate made of bronze, which served as a representation of Earth. In the center of the plate, was a large circle representing the Heavens appeared in which the lodestone was placed.
This circle represented the Heavens. The lodestone spoon itself symbolized the constellation the Great Bear also called Ursa Major , which contains the collection of stars known as the Big Dipper. Because of the properties of lodestone, the handle of the spoon always pointed towards the south.
In , the compass was first used for navigation. As early as 2, years ago, Chinese scientists may have understood that rubbing an iron bar with lodestone would magnetise the needle to point towards the north and south directions. Best mobile phones Tech News. Highest in 30 years! Vicky Kaushal grew up in a 10 by 10 house with no separate bathroom, kitchen - details here.
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