The metric system was created in 1791 at a meeting of delegates from France, England, and Switzerland. They agreed to create a unified measurement system, where each unit would start with its name (kilogramme, litre, etc.) followed by a number indicating its power. Each unit has a name and a symbol.
This system has been adopted by many countries around the world and is widely used in science, engineering, manufacturing, medicine, construction, Metric prefixes are commonly used in everyday life so it’s an important mathematical concept to grasp. In this article we explain the purpose of metric prefixes and describe the most common metric system prefix units.
What is a metric prefix?
A metric prefix is used to express multiples and submultiples of a given unit. In metric, that means multiplying or dividing the unit by ten, one hundred, one thousand, one million, one billion, one trillion, one quadrillion, one quintillion, etc.
A metric prefix can also refer to a fraction of a unit instead of a whole number. For example, a millimeter would be one thousandths of a meter, and a microgram would be one millionth of a gram.
What is the purpose of prefixes in the metric system?
Metric prefixes can be utilized to scale the base units to make them represent any size from a really huge quantity (using prefixes such as exa, tera, mega) to an incredibly tiny amount (using prefixes such has atto, femto, pico).
Scaling up or down when reporting measurement results is good practice because it makes it possible to keep measured quantities within reasonably sized numbers, say between values ranging from.0001 to 1.000. It is also useful to eliminate ambiguities regarding zero places holding in measurement reports, so that the number(s) of significant digits reflect the actual magnitude of the quantity. The prefixes convey how many decimal places are needed to express the numerical value
Why use prefixes in the metric system?
Metric measurements have their origins in ancient Greece, which is why they are written out in Greek terms. Before the introduction of the metric system, weights and measures were based on traditional systems of measurement such as the stone, the pound, the ounce and so forth. In order to facilitate comparison between these various units, they were given specific names.
For example, one stone was called a libra, a pound was called a pecunia, an ounce was called an uncia, and so forth. However, having a completely different name for every single weight, with little to no connection to each other was confusing. This is why the prefix system was created. It brought with it multiple advantages including:
- The names are self-explanatory
- They are easier to learn and remember
- They have a structure that is easy to follow
- The are universally understood
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How many prefixes are there in the metric system?
Since the metric system was first developed, there have only been four major changes to the base unit. These changes occurred in 1795, 1866, 1989, and 1991 respectively. Each change involved adding new prefixes to make it easier to express larger amounts. In addition, the old prefixes were replaced by newer ones so that the number of prefixes remained constant throughout. Today, there are a total of 20 prefixes in the metric system.
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What are the most common metric system prefix units?
Volume
The litre, millilitre, micro-litre, and nanoliter are common units of measurement for liquid volume. They are defined as equal to one thousandth of a litre, one millionth of a litre, ten millionths of a litre, and one billionth of a litre respectively. These units are based on the metric system, although some countries use the imperial system.
In Europe, the centilitre is often used for liquids and the decilitre is used less frequently. Bulk agricultural products such as grains, beers and wines, are often measured in hektar. Larger volumes are usually expressed in kilo-hectares, mega-hectares or giga-hectares.
Length
The length unit system is based on the metric system, where there are ten different base units, each one being subdivided into powers of 10. For example, the metre is divided into 1000 millimetres, while the kilogram is divided into 106 grams. Each unit has a prefix indicating how many times it is multiplied by itself. Thus, the metre is denoted m, the kilogram kg, the hectometre hm, the megameter mM, the gigameter Gm, the terameter Tm, and so on and so forth.
Time
The SI prefixes for units of time are mostly used for quantities smaller than one second. These include:
- Microsecond — 10−6 s 0.000001 s
- Millisecond — 10−3 s 0.001 s
- Centisecond — 0.01 s
How to remember metric system prefixes
A fun way for kids to remember the most important metric system prefixes is with the pneumonic “King Henry Died Drinking Chocolate Milk”. This takes kids through the 6 most commonly used prefixes in school, and in the correct order.
Below is a breakdown of the pneumonic:
- King- Kilo
- Henry- Hecta
- Died- Deco
- Drinking- Deci
- Chocolate- Centi
- Milk- Mili
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The metric system is used all across the world, so it is an important concept to learn. However, with so many different units all relating to different prefixes, it can be difficult to understand the concept. If these greek terms are confusing to you, you could benefit from the help of a tutor. At Tutorax, we are dedicated to ensuring you reach your full academic potential.
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