O scale

O scale (or O gauge) is a scale commonly used for toy trains and model railroading. Originally introduced by German toy manufacturer Märklin around 1900, by the 1930s three-rail alternating current O gauge was the most common model railroad scale in the United States and remained so until the early 1960s. In Europe, its popularity declined before World War II due to the introduction of smaller scales.

O gauge had its heyday when model railroads were considered toys, with more emphasis placed on cost, durability, and the ability to be easily handled and operated by pre-adult hands. Detail and realism were secondary concerns, at best. It remains a popular choice for hobbyists who enjoy running trains more than they enjoy other aspects of modelling, and collecting vintage O gauge trains is also popular. There is a market for reproduction and vintage style models also. A number of changes in recent years have addressed the concerns of scale model railroaders, making O scale more popular.

Scale

Scale or scales may refer to:

Common meanings

Places

Mathematics

Science

Scale length (string instruments)

When referring to stringed instruments, the scale length (often simply called the "scale") is considered to be the maximum vibrating length of the strings to produce sound, and determines the range of tones that string is capable of producing under a given tension. In the classical community, it may be called simply "string length." On instruments in which strings are not "stopped" or divided in length (typically by frets, the player's fingers, or other mechanism), such as the piano, it is the actual length of string between the nut and the bridge.

String instruments produce sound through the vibration of their strings. The range of tones these strings can produce is determined by three primary factors: the mass of the string (related to its thickness as well as other aspects of its construction: density of the metal/alloy etc.), the tension placed upon it, and the instrument's scale length.

On many, but not all, instruments, the strings are at least roughly the same length, so the instrument's scale can be expressed as a single length measurement, as for example in the case of the violin or guitar. On other instruments, the strings are of different lengths according to their pitch, as for example in the case of the harp or piano.

Scale (map)

The scale of a map is the ratio of a distance on the map to the corresponding distance on the ground. This simple concept is complicated by the curvature of the Earth's surface, which forces scale to vary across a map. Because of this variation, the concept of scale becomes meaningful in two distinct ways. The first way is the ratio of the size of the generating globe to the size of the Earth. The generating globe is a conceptual model to which the Earth is shrunk and from which the map is projected.

The ratio of the Earth's size to the generating globe's size is called the nominal scale (= principal scale = representative fraction). Many maps state the nominal scale and may even display a bar scale (sometimes merely called a 'scale') to represent it. The second distinct concept of scale applies to the variation in scale across a map. It is the ratio of the mapped point's scale to the nominal scale. In this case 'scale' means the scale factor (= point scale = particular scale).