A System of units Is a collection of units of measure and rules that relate these units to each other. In this sense, unit systems are understood as sets of standardized and uniform units of measurement.
Historically, the systems of units have played a fundamental role in science and commerce, since they have allowed to regulate and to unify multiple concepts.
Nowadays, the systems of units have been divided into two large groups: the metric system and the imperial system.
However, it is possible to find other systems of units in the world, such as natural, technical, decimal, cegesimal and Anglo-Saxon, among others.
However, most of these unit systems tend to derive from the same units of measurement, those given by metric or imperial systems.
Unit systems also relate to other important concepts such as magnitude. This refers to the numerical value that is given to everything that is measured.
In this sense, unit systems can measure magnitudes of force, mass, time, area, velocity, volume, length, among others.
It can be said that a system of units aims to measure the different magnitudes existing, making use of the same pattern, rules and group of units.
Classification of the systems of units
The systems of units were first devised in France in the late eighteenth century. They are born thanks to the need to be able to account for and measure things by making use of the same patterns or conditions.
However, these have evolved enormously over time as human needs change (fun, 2016).
The first system that was implemented was the metric decimal, however, today we have other examples of systems of units, as can be seen below:
Metric system
Historically, it was the first system of units proposed to unify the way the elements were measured and counted.
Its base units are the meter and the kilogram, and the multiples of the units of the same type must always increase on a decimal scale, that is, ten in ten.
This system was initially devised in France and later adopted by all European countries except the United Kingdom, which decided to adhere to its system of units known as the imperial system.
This system has evolved over time, being expanded and restructured to become the international system that we all know today (Alfaro).
Imperial system
The imperial system or Anglo-Saxon system of measures is a system composed of non-metric units that is currently used mainly in the United States.
Despite being a system devised in the United Kingdom, today it presents certain differences with the old system that was used in the United Kingdom.
For this reason, in the United States it is known as the Anglo-Saxon system and in the United Kingdom it is known as the imperial system.
Units of measurement in both countries are given the same names, however, their numerical equivalences often differ in magnitude (need, 2017).
The units of measure used are the foot, the inch, the mile, the yard, the league, the chain, the furlong, and the rood.
Natural system
The natural units or units of Planck was a system proposed by Max Planck in the late nineteenth century in order to simplify the way the physical equations are written.
In this sense, it contemplates the measurement of fundamental magnitudes (length, mass, time, temperature and electric charge).
It is useful because it allows comparing magnitudes more simply and eliminates the proportionality constants of the equations, making the results of the same can be interpreted independently of these constants.
These units are commonly referred to as the"units of god", since they eliminate the arbitrariness typical of other systems of units previously proposed by humans (Britten, 2017).
Cegesimal system
The cegesimal system or CGS system, is based on the units of centimeter, gram and second. From these three units is derived its name.
It was first raised in the 19th century by the German mathematician and physicist Johann Carl Friedrich Gauss to unify the units used in various technical and scientific fields.
Many physical formulas are easier to express thanks to the use of the cegesimal system, in this sense Gauss's goal was fully achieved and the expansion of a certain technical and physical term became possible in other areas of knowledge.
Over time, this system derived from the metric system was also adopted by the British Association of Advanced Science (BAAS) and BA today.
International System of Units
The international system of units or SI is the most popular system of units in the world today. It was adopted as a priority and unique by all the countries of the world except the United States, Burma and Liberia.
It is derived from the old metric system of decimal, for this reason today is also called the metric system.
Since 1960, and thanks to the XI General Conference of Weights and Measures, six basic units were established by which the metric system should be governed: second (s), meter (m), ampere (A), kilogram ), Candela (cd) and kelvin (K). Over time, the mole unit was added to measure chemical compounds.
It is a system of units that is based on fundamental physical phenomena. Its units are an international benchmark that serves as a basis for developing tools and measurement tools.
These instruments are in constant calibration and comparison to be fully unified (Britannica, 2017).
In this way, the international system has allowed a global equivalence between the elements that are measured, when using similar instruments that share the same units.
Thus, regardless of distance or place where reference magnitudes are taken, they will represent the same in any part of the world. Thanks to this, between the years 2006 and 2009, the international system was unified according to ISO standards.
References
- Alfaro, L.I. (s.f.). Unit I Unit Systems. HIdalgo: Autonomous University of the State of Hidalgo.
- Britannica, E. (2017). Encyclopædia Britannica . Obtained from International System of Units (SI): britannica.com
- Britten, E.B. (2017). I am learning . Obtained from System of units: I am - Learning
- Fun, M. i. (2016). Math is fun . Obtained from Metric System of Measurement: mathsisfun.com
- Need, S. and. (2017). com . Obtained from Systems of Measurement | Weights and Measures: skillsyouneed.com.