Heading North

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At a time, when the world was still a mysterious place full of untrodden territories, long before the introduction of the Global Positioning System (GPS) and Google Maps, people relied on several direction indicators to lead them through their travel, among which are the stars and the compass. Together, we shall unravel the mystery of the compass, its uses, and history.

What We Know

To this day, no one knows exactly when the compass was first used, or who invented it; what we know is that it dates back to the 11th century. The ancient Greeks were the first to discover the secrets of magnetism and observe the properties of the naturally magnetized lodestone, which may have contributed to the invention of the compass some hundreds years later. It is suggested that the Chinese were the first to use the compass, followed by the Europeans. However, other researchers claim that the compass may have been used by the Arabs, Europeans, and Chinese at roughly the same time, and that the invention was shared amongst them through trade.

Compass Types

The most popular compass is the magnetic compass; a typical old fashioned prototype would be made up of a magnetized needle and a piece of cork or wood. The needle should be attached to the wood and placed in a bowl of water. At first, the needle would spin then stop in alignment with Earth’s magnetic field, with one point of the needle indicating North and the other indicating South. Undoubtedly, modern models are much more advanced and sophisticated.

Another less common type is the gyrocompass, which has a rapidly spinning wheel the rotation of which interacts with the rotation of the Earth and points to the actual Poles of Earth. There is also the solar compass, which uses the position of the Sun to establish bearing and operates somewhat like a sundial.

Are Compasses Reliable?

Compasses were at first only used when the traditional direction indication methods depending on the Sun or stars were not feasible. However, as travelers started to understand compasses and the devices became more reliable, their use became more fashionable. To understand how reliable a magnetic compass is, we must shed light on the difference between the magnetic versus the geographical North.

The geographical North is the point where the lines of longitude meet at the Earth’s North Pole; as such, the North Pole is the geographical north. On the other hand, the magnetic north is where the lines of attraction meet and it is related to Earth’s magnetic field. The magnetic north refers to Ellesmere Island in Northern Canada; the magnetized needle in the compass always points to the magnetic north. Today, the difference between magnetic north and geographical north is 500 kilometers; as such, when using a compass, one must put the “declination” between the two into account.

Now, before looking down at the compass and thinking how simple it is compared to the GPS, think of its importance to ancient mariners, adventurers, and great explores. Thanks to the compass, Magellan and Christopher Columbus would not have navigated the vast oceans reaching for new lands.

References

nationalgeographic.org
theinstitute.ieee.org
tandfonline.com
gisgeography.com
prezi.com

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SCIplanet is a bilingual edutainment science magazine published by the Bibliotheca Alexandrina Planetarium Science Center and developed by the Cultural Outreach Publications Unit ...
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