Session 7: Length Conversion – Metric Units and Customary Units

Measurement is a concept that appears all the time in everyday life. To measure something is to determine the size, amount, or degree of a quantity or object, using standard or non-standard units. Measurements can be made of physical quantities such as length, mass, time, temperature, electric current, and luminous intensity, among others.

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Measurement of Length

Length is the measurement of the distance between two points, two things or two places. To measure the length of an object, one uses measuring tools such as rulers and measuring tapes. For instance, a pencil’s length can be measured in inches by using a ruler, while a feet scale can be used to determine the height of students in a classroom. Some of the units of length are miles, centimetres, kilometres, and yards. These units can be converted between one another.

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Length Conversion

Converting lengths from one unit to another is known as length conversion. For instance, kilometres can be converted to miles, feet can be converted to yards, and yards can be converted to millimetres. 

In our daily lives, we encounter numerous values of length, such as the length of a highway measured in kilometres or the length of a spoon measured in inches.

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Length Conversion in Metric Measurement System

By the 18th century, dozens of different units of measurement were commonly used throughout the world. Length, for example, could be measured in feet, inches, miles, spans, cubits, hands, and more. The lack of common standards led to confusion and significant inefficiencies in trade between countries. At the end of the century, the French government devised a system of measurement that could be used throughout the world. This system is known as the metric system. 

The Metric Measurement System, also known as the International System of Units (SI), is a globally recognized and standardized system of measurements that simplifies and unifies the units of length, mass, and capacity. The system is based on the metre, kilogram, and litre as the fundamental units of length, mass, and capacity, respectively.

In the metric system, the unit of length is the metre (m), which is defined as the distance travelled by light in a vacuum in 1/299,792,458 of a second. The metre is the base unit for measuring length, and other units are derived by multiplying or dividing the metre by powers of 10.

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Length Conversion in Customary Measurement System

The United States does not officially use the SI system. They follow their own measurement system called the United States Customary Measurement System. The customary units of length are based on the inch, foot, yard, and mile. The foot is the base unit for measuring length in the customary system.