scales

Scales is a term with multiple meanings across disciplines. In common usage, it refers to tools for measuring weight, musical systems, or the protective plates on animals, among other senses.

Scales as devices to measure mass include balance scales, which use a fulcrum and known masses, and spring scales, which measure force via calibrated springs. Modern scales may be electronic, using load cells and digital readouts. Calibration using standard weights is essential for accuracy.

In music, a scale is an ordered sequence of pitches used as a basis for melodies and harmonies. Common scales include major and minor scales in Western music, as well as pentatonic, modal, and synthetic varieties. Scales define a key and provide tonal center, influencing intervals, chord progressions, and melodic contour.

In biology, scales are the rigid, overlapping plates or scales on the skin of many reptiles, fish, and some mammals. They vary in size, shape, and arrangement and serve protection, moisture retention, and sometimes camouflage.

In geometry and cartography, a scale describes the ratio between a distance on a map or model and the corresponding distance in the real world. Scaling also denotes proportional enlargement or reduction of objects, and is described by a scale factor. The term’s precise meaning depends on context, but all senses relate to a relative measure or a covering.