How does a compass work

It must be level, and it tends to correct itself rather slowly when the platform turns. Because of this tendency, most ships and airplanes use gyroscopic compasses instead. A spinning gyroscope , if supported in a gimbaled frame and spun up, will maintain the direction it is pointing toward even if the frame moves or rotates. In a gyrocompass, this tendency is used to emulate a magnetic compass. At the start of the trip, the axis of the gyrocompass is pointed toward north using a magnetic compass as a reference.

A motor inside the gyrocompass keeps the gyroscope spinning, so the gyrocompass will continue pointing toward north and will adjust itself swiftly and accurately even if the boat is in rough seas or the plane hits turbulence. Periodically, the gyrocompass is checked against the magnetic compass to correct any error it might pick up. For more information on compasses, navigation and related topics, check out the links on the next page.

Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Outdoor Activities. How Compasses Work. Wondering why a compass always points north? Earth's Magnetic Field " ". Creating Your Own Homemade Compass " ". A needle or some other wire-like piece of steel a straightened paper clip, for example Something small that floats such as a piece of cork, the bottom of a Styrofoam coffee cup, a piece of plastic or the cap from a milk jug A dish, preferably a pie plate, 9 to 12 inches 23 - 30 cm in diameter, with about an inch 2.

The Gyroscopic Compass A magnetic compass like the one created on the previous page has several problems when used on moving platforms like ships and airplanes. Cite This! Try Our Sudoku Puzzles! And making things even more difficult for the compass-wielding navigator, the magnetic North Pole isn't even a stationary point. As the Earth's magnetic field changes, the magnetic North Pole moves. Over the last century, it has shifted more than miles 1, kilometers toward Siberia, according to scientists at Oregon State University.

This difference between true north and the north heading on a compass is an angle called declination. Declination varies from place to place because the Earth's magnetic field is not uniform it dips and undulates. These local disturbances in the field can cause a compass needle to point away from both the geographic North Pole and the magnetic North Pole. This allows the needle to better react to nearby magnetic fields.

This is how navigators are able to discern north. The Earliest compasses were water compasses invented by the Chinese during the Song dynasty. These were a magnetized piece of metal floating in a bowl of water.

The water provides the first frictionless pivot needed for making a working compass. The compass later came into common use in the west during the 14th century AD. This led to what is now known as the Age of Exploration where major European powers started further exploration of the World including North and South America.