Understanding the Depricated CGS and MKS Systems in Units

When discussing the metric system, one often encounters terms like CGS (Centimeter-Gram-Second) and MKS (Meter-Kilogram-Second) systems. However, these systems have largely been replaced by the International System of Units (SI). This article aims to provide a comprehensive understanding of the CGS and MKS systems, their origins, and why they have been largely replaced by the SI system.

Introduction to the CGS and MKS Systems

The modern metric system, known as the International System of Units (SI), has largely replaced the CGS and MKS systems. However, it is still beneficial to understand the historical context and differences between these systems. Both CGS and MKS systems were developed as a way to provide a consistent and coherent framework for measurement, but they were eventually supplanted by the SI system in the mid-20th century due to its broader applicability and comprehensiveness.

Development of the MKS System

The MKS system evolved from the original French mercantile metric system, which was based on the meter, kilogram, and second. In 1948, the MKS system was further developed into the MKSA system, which added the ampere for modern electrical measurements. The MKSA system replaced the earlier MKS system because the MKS system did not include modern electrical units (the ampere) and it introduced a clear distinction between mass and force. Force was measured in newtons, and the kilogram-force was deprecated. The MKSA system was then superseded by the SI system in 1960 when the World Conference on Weights and Measures (Conférence Générale des Poids et Mesures, CGPM) adopted the modern metric system as the International System of Units.

Origins and Usage of the CGS System

The CGS system is based on the centimeter, gram, and second. While the CGS system has been widely used in various scientific and engineering contexts, particularly in the field of physics, its use has diminished significantly over time. One of the key reasons for this is the presence of numerous peculiar and non-standard electrical units in the CGS system. Although the CGS system introduced "practical units" that were nearly identical to those of the MKSA system, these units were favored by physicists but not widely adopted in practical applications.

Deprecation of CGS and MKS Systems

All units specifically named in the CGS system, which were explicitly deprecated by the SI, should no longer be used in practice. The SI system, introduced in 1960, has become the standard for global measurement. It provides a comprehensive and universally accepted framework for all kinds of measurements. The adoption of the SI system has led to a standardized approach to scientific and engineering practices, enhancing consistency and precision in measurements.

Conclusion: Learning the SI System

Unless one is studying the history of the metric system in a formal course, the knowledge of the CGS and MKS systems is less relevant today. The SI system has largely replaced these older systems due to its broader applicability, precision, and consistency. Therefore, for students, engineers, and professionals in scientific and technical fields, learning the SI system is essential to ensure compliance with international standards and to maintain accuracy and reliability in their work.

Related Articles and Resources

For further reading and resources on the metric system and SI units, you may want to explore the following links:

BIPM: The International Bureau of Weights and Measures NIST: International System of Units (SI) ISO 80000-1, Quantities and units – Part 1: General

By delving into these resources, you can gain a deeper understanding of the SI system and its application in various fields of study and practice, ultimately enhancing your knowledge and skills in working with modern measurement systems.