Order of magnitude in the context of "Unit prefix"

The long and short scales are two powers of ten number naming systems that are consistent with each other for smaller numbers, but are contradictory for larger numbers. Other numbering systems, particularly in East Asia and South Asia, have large number naming that differs from both the long and the short scales. Such numbering systems include the Indian numbering system and Chinese, Japanese, and Korean numerals. Much of the remainder of the world has adopted either the short or long scale. Countries using the long scale include most countries in continental Europe and most that are French-speaking, German-speaking and Spanish-speaking. Use of the short scale is found in most English-speaking and Arabic-speaking countries, most Eurasian post-communist countries, and Brazil.

For powers of ten less than 9 (one, ten, hundred, thousand, and million), the short and long scales are identical; but, for larger powers of ten, the two systems differ in confusing ways. For identical names, the long scale grows by multiples of one million (10), whereas the short scale grows by multiples of one thousand (10). For example, the short scale billion is one thousand million (10), whereas in the long scale, billion is one million million (10), making the word 'billion' a false friend between long- and short-scale languages. The long scale system includes additional names for interleaved values, typically replacing the word-ending '-ion' with '-iard'.

There are 13 lakes of at least five acres (two hectares) within the borders of Minneapolis in the U.S. state of Minnesota. Of these, Bde Maka Ska is the largest and deepest, covering 421 acres (170.37 ha) with a maximum depth of 89.9 feet (27.4 m). Lake Hiawatha, through which Minnehaha Creek flows, has a watershed of 115,840 acres (468.79 km), two orders of magnitude larger than the next largest watershed in the city. Ryan Lake, in the city's north, sits partially in Minneapolis and partially in neighboring Robbinsdale. Certain other bodies of water are counted on some lists of Minneapolitan lakes, though they may fall outside the city limits or cover fewer than five acres.

Many of Minneapolis's lakes formed in the depressions left by large blocks of ice after the retreat of the Laurentide Ice Sheet at the end of the last glacial period and now overlie sandy or loamy soils. Before the appearance of white settlers, the Dakota harvested wild rice from the lakes. In the early 1800s, the lakes' shorelines were marshy, deterring large-scale settlement and development by white residents though an experimental Dakota agricultural community, Ḣeyate Otuŋwe, was founded on the banks of Bde Maka Ska by Maḣpiya Wic̣aṡṭa in 1829. In the 1880s, landscape architect Horace Cleveland foresaw Minneapolis's growth and made a series of recommendations to the city's Board of Park Commissioners to acquire land along Minnehaha Creek, near Minnehaha Falls, and around several lakes in the southwest portion of the city in order to form a robust, interconnected park system that would aesthetically and morally benefit the city's residents. Board president Charles M. Loring heeded Cleveland's advice and bought the land, later developed into a robust system of parks by Theodore Wirth. During this time, many of the lakes were reformed by the Board of Park Commissioners through draining, dredging, shoreline stabilization, and the construction of parkways around their perimeters. Property in neighborhoods surrounding the lakes grew desirable, especially by the "Chain of Lakes", five lakes in the southwestern portion of the city (Maka Ska, Harriet, Isles, Cedar, and Brownie) that were joined by artificial channels.

In mathematics, the magnitude or size of a mathematical object is a property which determines whether the object is larger or smaller than other objects of the same kind. More formally, an object's magnitude is the displayed result of an ordering (or ranking) of the class of objects to which it belongs. Magnitude as a concept dates to Ancient Greece and has been applied as a measure of distance from one object to another. For numbers, the absolute value of a number is commonly applied as the measure of units between a number and zero.

In vector spaces, the Euclidean norm is a measure of magnitude used to define a distance between two points in space. In physics, magnitude can be defined as quantity or distance. An order of magnitude is typically defined as a unit of distance between one number and another's numerical places on the decimal scale.

An order of magnitude of time is usually a decimal prefix or decimal order-of-magnitude quantity together with a base unit of time, like a microsecond or a million years. In some cases, the order of magnitude may be implied (usually 1), like a "second" or "year." In other cases, the quantity name implies the base unit, like "century." In most cases, the base unit is seconds or years.

Prefixes are not usually used with a base unit of years. Therefore, it is said "a million years" instead of "a megayear." Clock time and calendar time have duodecimal or sexagesimal orders of magnitude rather than decimal, e.g., a year is 12 months, and a minute is 60 seconds.

An Olympic-size swimming pool is a swimming pool which conforms to the regulations for length, breadth, and depth made by World Aquatics (formerly FINA) for swimming at the Summer Olympics and the swimming events at the World Aquatics Championships. Different size regulations apply for other pool-based events, such as diving, synchronized swimming, and water polo. Less onerous breadth and depth regulations exist for lesser swimming competitions, but any "long course" event requires a course length of 50 metres (164 ft 0.5 in), as distinct from "short course" which applies to competitions in pools that are 25 metres (82 ft 0 in) in length (or 75 feet (22.9 m) in the United States). If touch pads are used in competition, then the distance is relative to the touch pads at either end of the course, so that the pool itself is generally oversized to allow for the width of the pads.

An Olympic-size swimming pool is used as a colloquial unit of volume, to make approximate comparisons to similarly sized objects or volumes. It is not a specific definition, as there is no maximum limit on the depth of an Olympic pool. The value has an order of magnitude of 1 megaliter (ML). Some style guides caution against the hyperbole of describing any relatively large pool as "Olympic-size[d]".

This is a tabulated listing of the orders of magnitude in relation to pressure expressed in pascals. psi values, prefixed with + and -, denote values relative to Earth's sea level standard atmospheric pressure (psig); otherwise, psia is assumed.

The following are examples of orders of magnitude for different lengths.