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Ounce

physical science Maturity 11-13 Next article →

An ounce is a way to measure many different things. It can measure how heavy something is, which is called mass. It can also measure volume, which is how much space a liquid takes up.

People use different kinds of ounces depending on what they are weighing. Most people in the United States use the avoirdupois ounce. This is the standard unit for many everyday items. It helps us know exactly how much something weighs.

There are a few different ways the ounce works. The avoirdupois ounce is exactly 28.349523125 grams. In this system, sixteen ounces make up one pound. One avoirdupois ounce is also equal to 437.5 grains. Another type is the troy ounce, which is used for precious metals. This includes things like gold, silver, and platinum.

A troy ounce is heavier than a regular ounce. It weighs exactly 31.1034768 grams and equals 480 grains.

History shows us that the ounce has changed over time. The name comes from the Ancient Roman word uncia. This word meant one-twelfth of a Roman pound. The Roman uncia weighed about 27.4 grams.

Over many centuries, the word moved into different languages. It went from Latin to Old English and Middle English. In the past, many different versions of the ounce existed. Different trades and different lands had their own rules.

Many special ounces have been used in different places. For example, the Maria Theresa ounce was used in Ethiopia. It weighed 28.0668 grams and was linked to a coin called a thaler. The Dutch once used a metric ounce called an ons. This was defined as 100 grams in 1820.

In England, a Tower ounce was used at the Tower of London. King Henry VIII abolished it in 1527 to use the troy ounce instead. There were even different ounces used by doctors, called apothecaries' ounces.

Today, we see ounces in many parts of our lives. You might see fluid ounces on a bottle of juice. An imperial fluid ounce is 28.4130625 milliliters. A US customary fluid ounce is 29.5735295625 milliliters.

You can also find ounces used to describe heavy fabric. For example, denim might be called 16 oz denim. Even tiny parts in electronics use ounces to measure copper thickness. This helps engineers understand how much metal is on a circuit board.

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