The kelvin (K), the SI unit of temperature, has been redefined with a new definition to take effect from May 20th, 2019, based on Boltzmann’s constant. This unit was originally defined as 100/27,316 of the triple point of pure water. Temperature is a crucial measurement in human life, and systems, technologies, methods, and units have been constantly developed to quantify and represent it accurately. The new definition of kelvin reflects a continuing process of improvement in this area.

# Understanding the New Definition of Kelvin, the SI Unit of Temperature

Temperature is an essential aspect of our daily lives, influencing everything from cooking and heating to the functioning of our bodies. For centuries, we have been refining the methods, systems, and units for quantifying and representing temperature. Now, the kelvin (K), the International System of Units (SI) unit of temperature, has a brand new definition.

## What is Kelvin?

Kelvin (K) is the basic unit of thermodynamic temperature measurement in the International System of Units. It is used to quantify the intensity of heat or energy in a given object or entity and is utilized in various scientific fields such as physics, chemistry, and engineering.

## What is the New Definition of Kelvin?

The General Conference on Weights and Measures in 2018 decided that beginning May 20, 2019, the definition of the kelvin (K) will be such that Boltzmannâ€™s constant is 1.380649 Ã— 10^-23 joule per kelvin. This decision is a ground-breaking change from the prior definition which was 100/273.16 times the triple point of pure water.

This update will simplify the definition of the kelvin and create a better distinction between the kelvin and other SI units such as the mole and the ampere. The previous definition of the kelvin suffered from drawbacks in terms of precision, as the triple point is not a perfect thermometric fixed point, unlike absolute zero.

To provide some context, Boltzmann’s constant is used often in physics to relate the average kinetic energy of a particle or molecule in a gas to the temperature of the system. It is also the proportionality constant relating entropy to the natural logarithm of the number of microstates (W) of the system.

## What are the Benefits of the New Definition?

The new definition of the kelvin has numerous advantages and benefits. One of these is a significant increase in measurement accuracy and precision. This change means that anyone who measures temperature can now define the kelvin with much higher uncertainty specifications, making temperature measurements more precise and meeting improved scientific standards.

Additionally, the updated definition has facilitated a better understanding of the fundamental nature of thermodynamics. This knowledge will enhance our understanding of industrial processes and chemical reactions, aiding in the development of materials and technologies in the future.

In The essence of the matter, the new definition of the kelvin is a significant milestone for the scientific and industrial communities worldwide. It will lead to a more stringent standard for temperature measurement and provide better insight into thermodynamics, opening up new avenues for scientific exploration and technological advancements.