One of the most important inventions of early humanity was the compass.

The compass has aided human navigation around the earth for centuries.

Despite being a critical technology in the development of transportation, it actually took centuries

between the discovery of its underlying principles

and its eventual use as a practical tool for navigation.

And even though it was discovered over 2,000 years ago,

compasses are still a vital tool today.

Learn more about the compass and how it helps humanity find its way on this episode of

Everything Everywhere Daily. Before I get into the history of the compass I should explain a little bit about how it works.

As I'm sure all of you are aware, a compass uses a magnetic metallic piece of metal that will orientate itself in the presence of a magnetic field.

This effect will manifest in the presence of any magnetic field, including artificially created ones.

However, unless you happen to be standing next to something magnetic,

the magnetic object is going to align itself with the natural magnetic field of the Earth.

The Earth can be thought of as a giant bar magnet,

just as a giant bar magnet.

Just as a bar magnet has a north and south pole, so does the Earth.

The magnetic north and south poles of the Earth are not the same thing as the geographic poles.

The geographic poles are steady, but the magnetic poles usually

are some distance away from the geographic poles and they're always moving.

So in summary, a compass is just a small magnet that aligns itself with a very big magnet, which happens to be the earth.

The compass effect, which I just described, was first discovered sometime during the Han Dynasty in China about 2,000 years ago.

Unlike other great Chinese inventions, who discovered the compass effect and exactly when it was discovered isn't precisely known?

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