Inch facts for kids
The inch is a unit of length used in some countries. It's part of the Imperial system and the U.S. customary system.
You might see "in" or a double quote mark (") as a short way to write inches. There are 12 inches in one foot. One inch is exactly the same as 2.54 centimetres.
The word "inch" comes from an old Latin word, uncia. This word meant "a twelfth part," which makes sense because an inch is one-twelfth of a foot!
How the Inch Was Created
The inch wasn't always the same size. Long ago, it was first defined as the length of three barleycorns placed end to end.
In 1959, several countries worked together to make the inch a standard size. The United States, the United Kingdom, South Africa, Australia, New Zealand, and Canada signed a special agreement. This agreement was called the International Yard and Pound Treaty.
This treaty made the international yard equal to 0.9144 metres. From this, the exact size of the inch and other related units were officially set.
Where Inches Are Used Today
In the United States, people often use inches more than millimetres or centimetres. This is common for everyday measurements. In most other parts of the world, metric units (like centimetres) are used almost all the time. Scientists usually use metric units too.
In the United Kingdom, you'll see road signs showing vehicle heights in feet and inches. This helps drivers know if their vehicle can fit under a tunnel. However, places like Theme parks often use metres for height limits. Many people in the UK measure their own height in feet and inches. But for official medical records, height must be written in metric measurements.
In Canada, people use a mix of centimetres and inches for height. Older Canadians often use Imperial units more. Because they are exposed to many American phrases, younger Canadians usually understand both Imperial and metric systems well.
Other Commonwealth countries, like Ireland, Australia, New Zealand, South Africa, and Jamaica, also use inches. How much they use it varies, from daily use to mainly by older people.
Images for kids
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A fire hydrant marked as 3-inch
See also
In Spanish: Pulgada para niños
