Some students may be interested to consider why bearings are always measured from north. The Earth rotates about an axis through its north and south poles. The Pole Star, which lies approximately ‘above’ the north pole, appears to remain fixed while the other stars turn about it. Early navigators used this ‘fixed’ star to set their courses in the northern hemisphere. Later, magnetic compasses were used, which pointed in approximately the same direction, so this was naturally chosen as the base direction for taking bearings.

Global Positioning System (GPS)

The Global Positioning System (GPS) is now widely used in military, commercial, civil and leisure applications. Positions are fixed or tracked using satellite signals. Hand-held GPS devices, and systems fitted in vehicles, are increasingly common. Students can find out how this technology works using basic triangulation techniques, and discover the huge range of applications it has in real life.