# Basic Concepts of Measurement

In 1821, after studying the various units of measurement used by the 22 states, Secretary of State John Quincy Adams determined that the U.S. Customary System was sufficiently uniform and required no changes. Most people actually believed that the metric system wouldn’t survive Napoleon’s rule. They were wrong, however, and by the time the American Civil War ended, most of Europe had turned metric — other than the proud British of course. When the British Empire colonized North America hundreds of years ago, it brought with it the British Imperial System, which was itself a tangled mess of sub-standardized medieval weights and measurements.

### What are the 3 measurement systems?

Systems of Measurement: there are two main systems of measurement in the world: the Metric (or decimal) system and the US standard system. The US Standard system uses units that have no predictable relationship to each other. For example, there are 2 cups in a pint, but 4 quarts in a gallon.

In the 1970s, it was used as a standard parameter on the U.S. to made trucks and cars. However, the US isn’t pressured by the same trading problems as the UK. You don’t need the metric system to measure one car made in Japan, or one iPad from China, or to license an SQL Server to Germany.

## Tools

Starting in the 18th century, modernized, simplified and uniform systems of weights and measures were developed, with the fundamental units defined by ever more precise methods in the science of metrology. The discovery and application of electricity was one factor motivating the development of standardized internationally applicable units. The International System (abbreviated SI, for Système International, the French name for the system) was adopted in 1960 by the 11th General Conference on Weights and Measures.

Whatever the measurable property, be it mass, length or time, the underlying fundamentals remain the same. Throughout history various systems of measurement have been used, without a need for standardization. The French Revolution gave rise to the metric system, and this has spread around the world, replacing most customary units of measure. In most systems, length (distance), mass, and time are base quantities. Several systems of measurement exist, each one comprising units whose amounts have been arbitrarily set and agreed upon by specific groups.

## Non-standard units

Some of these are only used in scientific applications, so you are unlikely to come across them in day to day usage. The metric system was officially adopted as a standardised system of measurement by the French in the late 18th century, although it was ‘invented’ over a century earlier. Believe it or not, the length of a ‘metre’ was derived from measurements of the earth’s circumference, which at the time aroused much curiosity and suspicion! However, it is the simplicity of the system that led to its rapid adoption throughout much of the industrialised world. The Imperial System is also called The British Imperial because it came from the British Empire that ruled many parts of the world from the 16th to the 19th century.

An expanded and modified version of the metric system, the International System addresses the needs of modern science for additional and more accurate units of measurement. The key features of the International System are decimalization, a system of prefixes, and a standard defined in terms of an invariable physical measure. When the large numbers of bolt-type fasteners used in the USA follow the one or other measurement scales, the actual difference between metric or SAE and their respective sockets are as similar to yards and meters.

And this is where the need for consistency in measuring values comes. The earliest recorded systems of weights and measures originate in the 3rd or 4th millennium BC. Even the very earliest civilizations needed measurement for purposes of agriculture, construction, and trade. Early standard units might only have applied to a single community or small region, with every area developing its own standards for lengths, areas, volumes and masses. With development of manufacturing technologies, and the growing importance of trade between communities and ultimately across the Earth, standardized weights and measures became critical.

He also declared that it would only be a matter of time before decimal numbers were used for currencies and measurements. His notation for decimal fractions was clumsy, but this was overcome with the introduction of the decimal point, generally attributed to Bartholomaeus Pitiscus who used this notation in his trigonometrical tables . When SAE, metric sized sockets come with the measurement in inches and widely used for domestic vehicles, most modern vehicles mainly use metric measurements. It’s very crucial to choose SAE and metric depending on your requirements or store of your garage will ensure you always have the best tool for the job.

While the United States Customary System remains the most commonly used system of measurement in the United States, the International System is accepted all over the world as the standard system for use in science. The sockets of this standard are typically marked on fractions on an inch for example 1/2″, 3/8″, and 13/16″, etc.

In 1790, secretary of state Thomas Jefferson made an analysis of the matter and felt reluctant to stir his country towards the decimal-based metric system — at the time still a fledgling standard born in France. The International System of Units (abbreviated SI, from the French Système international d’unités) is the metric system used in science, industry, and medicine. Depending on your age and geographic location, you might be very familiar with the “imperial” system, which includes units such as gallons, feet, miles, and pounds. The imperial system is used for “everyday” measurements in a few places, such as the United States.

By the time America proclaimed its independence in 1776, the former colonies still had trouble measuring uniformly across the continent. In fact, the forefathers knew this well and sought to address the problem. The first step was granting Congress the power “to coin Money … and fix the Standard of Weights and Measures,” as stated in Article I, Section 8 of the newly formed Constitution.

Each of them represents a varying standard which may or nearly matching sizes of the other. Depending on our needs and requirements, we can differentiate which sockets Set should I need both metric and SAE sockets or not. Measurement seems like a simple concept and on the surface it is just a representation of numbers and their quantifying units.

• SAE, or standard size, use the imperial measurement system we invented in the USA.
• Metric fasteners are used on imported cars, and SAE fasteners are used on domestic (USA) made cars.
• The difference between Metric and SAE sockets is similar to the difference between yards and meters.

As far as science and industry go, nowadays most work in SI units. So, at least for now, Americans are still fine without the metric system though sometimes problems and confusions surrounding the conversion can cause disasters. For instance, one conversion error between US and metric measurements sent a \$125 million NASA probe to its fiery death. It’s important to note, however, that even if US representatives had traveled to Paris, they most likely wouldn’t have returned with favorable news.

The difference between Metric and SAE sockets is similar to the difference between yards and meters. Metric fasteners are used on imported cars, and SAE fasteners are used on domestic (USA) made cars. SAE, or standard size, use the imperial measurement system we invented in the USA. In today’s world however there is a strong necessity for uniformity in measuring data.

The early unit was a grain of wheat or barleycorn used to weigh the precious metals silver and gold. Larger units preserved in stone standards were developed that were used as both units of mass and of monetary currency. The pound was derived from the mina used by ancient civilizations.

People use the different units of measure so frequently in daily life that their significance sometimes takes backstage. Right from exchange of currency to filling up gas and measuring time, units are practically everywhere!

The story of how Jefferson’s full vision for the new measurement system came close to displacing the Gunter chain and the traditional acre, but ended up not doing so, is explored in Andro Linklater’s Measuring America. Decimal numbers are an essential part of the metric system, with only one base unit and multiples created on the decimal base, the figures remain the same. Although the Indians used decimal numbers for mathematical computations, it was Simon Stevin who in 1585 first advocated the use of decimal numbers for everyday purposes in his booklet De Thiende (old Dutch for ‘the tenth’).

## Weights and Measures

of the “standard” proposed by Wilkins over a century previously. This would have equated to 11.755 English inches (29.8 cm) or 13.06 English inches (33.1 cm).

Like Wilkins, the names that he proposed for multiples and subunits of his base units of measure were the names of units of measure that were in use at the time. The great interest in geodesy during this era, and the measurement system ideas that developed, influenced how the continental US was surveyed and parceled.

Metrication is complete or nearly complete in almost all countries. US customary units are heavily used in the United States and to some degree in Liberia. U.S. units are used in limited contexts in Canada due to the large volume of trade; there is also considerable use of Imperial weights and measures, despite de jure Canadian conversion to metric.

There are primarily two internationally accepted standards of weights and measurements. The English system is based on yards/feet/inches whereas the metric system includes the meter/centimeter/millimeter. At a basic level the metric system is apparently broken down in ratios of 10 units while the English system is based on a system of 12 units. Although both systems have gained widespread acceptance and application, when it comes to converting values from one of the systems to another, that is an entirely different story altogether! Seemingly unrelated in numerical terms, the metric and English systems are still very useful measurements and it is relatively simple to represent a figure in meter as it is in yards, just by tweaking numbers here and there.

## Measurement system

US customary units, however, are still the main system of measurement in the United States. While some steps towards metrication have been made (mainly in the late 1960s and early 1970s), the customary units have a strong hold due to the vast industrial infrastructure and commercial development.

But in most of the world (including Europe) and in all scientific circles, the SI system is in common use. Both imperial units and US customary units derive from earlier English units. Imperial units were mostly used in the former British Empire and the British Commonwealth, but in all these countries they have been largely supplanted by the metric system. They are still used for some applications in the United Kingdom but have been mostly replaced by the metric system in commercial, scientific, and industrial applications.

### What is a standard system of measurement?

The second meaning of standard unit refers to a unit of particular set of units of measurement called the standard system (versus the metric system). The standard system includes the standard units of the foot, the pound (mass), and the gallon. United States customary units, used predominantly in the United States.

After the U.S gained independence from Britain, the new American government decided to keep this type of measurement, even though the metric system was gaining in popularity at the time. When weighing of goods began, units of mass based on a volume of grain or water were developed. The diverse magnitudes of units having the same name, which still appear today in our dry and liquid measures, could have arisen from the various commodities traded. The larger avoirdupois pound for goods of commerce might have been based on volume of water which has a higher bulk density than grain. The grain was the earliest unit of mass and is the smallest unit in the apothecary, avoirdupois, Tower, and troy systems.

Image via Wiki Commons.That’s right — the three countries which are not using the metric system are Liberia, Myanmar and of course… the United States of America. Why is the United States so keen on preserving the imperial system? In short, it’s not because Americans hate the metric system — it’s because they hate change, just like the rest of world. But in an ever-connected world, can the US afford not to line up to a standard that everybody else seems to adhere to? As we’ll learn, this resistance to change comes at a cost but at the same time, change also has a cost.