Federwaagen

Federwaagen, the plural form of Federwaage in German, refers to spring scales—mechanical devices that measure weight by the extension of a spring according to Hooke's law. A spring is anchored at one end; the other end bears the object to be weighed. As gravity pulls on the object, the spring stretches, and a connected pointer or graduated scale displays the force.

The force F equals kx, where k is the spring constant and x the extension. The instrument can be graduated in newtons or, if calibrated for a constant local gravity, in kilograms of mass. Readings depend on gravity; temperatures and aging of the spring can affect sensitivity and zero stability.

Variants and use: Hanging spring scales are common for groceries, luggage, or fishing; tabletop and pocket versions cover smaller weights. Some models use a dial display, while others rely on a simple scale with a moving pointer. Calibration and regular zeroing are important to maintain accuracy.

History and context: The principle is rooted in Hooke's law, and spring balances have been used since at least the 17th or 18th century as simple, robust weighing devices. In modern practice, many scales have shifted to electronic sensors, but traditional Federwaagen remain in use where mechanical operation without electricity is advantageous. See also balance scales and digital scales for related weighing technologies.