Ounce

The ounce is the name for a number of different units of Mass ('''oz'''), and also of two units of Fluid Volume ('''fl oz''') and of one unit of Force , the '''ounce-force''' ('''ozf'''). See Imperial System Of Units and U.S. Customary Units for more about the frameworks within which these units are defined.

avoirdupois ounce defined by the Avoirdupois System Of Mass (see Pound (mass) ). There are 16 ounces in the avoirdupois pound. The avoirdupois ounce is approximately 28.35 Gram .

troy ounce defined by the Troy System Of Mass . In troy weight, there are 12 ounces in a pound, and a troy pound is 5760 grains (about 373.24 g), rather than 7000 (about 453.59 g). ''Note:'' at roughly 31.104 g, the troy ounce is about 10 per cent more than the more-common avoirdupois ounce. These troy ounces are now used only when weighing precious metals like gold, platinum and silver. One ounce of gold is always 31.1 g. "Maria Theresa Ounce" was once introduced in Ethiopia and some European countries, which was equal to 31.1025 g.

apothecaries' ounce defined by the now-obsolete Apothecaries' System Of Mass . This ounce was the same size as the troy ounce, and its symbol was (2125).

The Fluid Ounce unit of volume also exists in the two versions of 28.41 ml (Imperial) and 29.57 ml (U.S.).

The ounce-force (see Pound-force ) is the force exerted by a mass of 1 oz avoirdupois at the Standard Acceleration Of Gravity , usually borrowing the value which is official for defining Kilograms-force , 9.80665 m/s². Thus 1 ozf is approximately 278.0 Millinewton .

METRIC REDEFINITIONS

Some countries have redefined their ounces to fit in with the metric system.

The Dutch have redfined their ounce (in Dutch , ons) as 100 g (much more than a traditional ounce). This was adopted along with the introduction of the metric system together with a redefinition of the Dutch pound (''pond'') as 1 kg. (Though the ''ons'' of 100 g remains in informal usage, this ''pond'' as a kilogram has fallen by the wayside, replaced by the Metric Pound of 500 g adopted in other countries.)

The Chinese used to have a traditional ounce known as a Tael (in Chinese, 两 ''liǎng'') of varying value. This has now been rounded off to 50 grams.

RELEVANT ARTICLES

Weights And Measures

Hides/leathers thickness is measured by a gauge in ounces or millimeters. An '''ounce''' equals '''1/64''' inch in this application
Source: P.17'Leather Facts' 3rd Edition, 1994. Published by New England Tanners Club.

EXTERNAL LINKS

http://www.unc.edu/~rowlett/units/dictO.html#ounce

http://www.unc.edu/~rowlett/units/dictF.html#fluid_ounce

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