What is a chain?
The chain is a unit of length measurement commonly used in surveying and land measurement. It is primarily used in countries that follow the imperial system of measurement, such as the United States and the United Kingdom. One chain is equal to 66 feet or 20.1168 meters. It is further divided into 100 links, with each link measuring 0.66 feet or 7.92 inches.
The chain was historically used for measuring large areas of land, such as farms or estates. Surveyors would use chains to measure distances between points and establish boundaries. The use of chains allowed for more accurate measurements compared to other methods available at the time. Today, the chain is still used in some specialized fields, such as civil engineering and land surveying, although it has been largely replaced by more modern and precise measurement tools like GPS.
What is a millimeter?
A millimeter is a thousandth of a meter (1/1000) which is the SI (International System of Units) unit of length. It is normally used to measure small lengths like the thickness of a sheet of paper or the dimensions of a small object.
One millimeter is approximately equal to 0.03937 inches (about 1/25th). Presicely there are 25.4 millimeters in an inch and it is often used in science and engineering. It is used in countries that have adopted the metric system.
You may come across millimeters when measuring the size of electronic components, jewelry or even the thickness of a fingernail.