kompasser

Kompasser, commonly called compasses, are instruments that indicate direction. The most familiar type is the magnetic compass, which aligns a magnetized needle or card with the Earth's magnetic field to point toward magnetic north. In addition, gyrocompasses and digital compasses offer alternative methods for determining direction, the latter using magnetometers and other sensors in devices such as smartphones and cars.

History: The magnetic compass was developed in China and entered wide use in the medieval world, spreading to the Islamic world and Europe. It revolutionized navigation and enabled longer sea voyages, contributing to the era of exploration. The gyrocompass, developed in the 19th and 20th centuries, relies on angular momentum rather than magnetism and points to true north, making it valuable on ships and aircraft where magnetic disturbances are common.

Construction and operation: A typical magnetic compass contains a pivoting magnetized needle or card inside a sealed housing, often with a damping fluid. The device must be calibrated for magnetic declination—the angle between magnetic north and true north that varies by location—to interpret maps correctly. Nearby ferrous metal, electronics, or magnetic anomalies can cause deviation and reduce accuracy.

Uses and limitations: Compasses are widely used in navigation, outdoor activities, surveying, and geophysics. Digital compasses require periodic calibration. Accuracy decreases near the magnetic poles and in environments with strong magnetic interference; in such conditions, users may rely on alternative methods or instruments.