Measuring By Science, Not Objects

New measurement definition for kilogram “a big step for science.”

Weight on a scale in a laboratory environment

Perhaps you have heard that in ancient times, humankind developed its systems for measurement by measuring objects and body parts. A foot was the length of a human foot. An inch was the length of three grains of barley laid end-to-end. Even the scientific metric system has its roots in using objects to determine units of measure.

In 1790, the kilogram was originally defined as the mass of one liter of water. In order to make the unit of measure more standardized, the kilogram was later defined by the weight of a polished metal cylinder (“Le Grand K”) cast in 1879 and kept under lock and key just outside of Paris. This did not change until very recently.

A group of scientists from 60 countries met in Versailles, France, in Nov. 2018 to vote on defining the kilogram, not using a golf-ball-sized piece of metal, but instead based on the laws of nature.

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Dr. Zeina J. Kubarych is a leader with the Physical Measurement Laboratory of the National Institute of Standards and Technology (NIST), based in Gaithersburg, Maryland. She was among the scientists who met in Versailles and voted unanimously on new definitions, not just of the kilogram but also of three other units of measure – the Kelvin, the Ampere and the Mole.

Dr. Kubarych believes that these changes, helping to more accurately define units of measure, will have a positive impact on industries around the world, including biotechnology.

“I definitely see an impact: the new definition allows for realization of mass at any desired level. Therefore we’re no longer limited to a one-point realization and scaling. This in turn allows for more direct and accurate measurements,” she said via email.

At biotechnology leader CSL Behring, research and development scientists have given a lot of thought to this topic and how it might impact the work they do on behalf of patients around the world.

“Accurate and precise measurement is so central to what we do,” said David Boerema, Associate Director, Bioanalytical Sciences, at the rare disease company’s Kankakee, Illinois, facility. He said that while he does not foresee these changes having an immediate effect on the day-to-day work of scientists at CSL Behring currently, the changes will likely influence the industry in years to come.

“The true impact will likely be realized in the future as these improved definitions are leveraged by measurement instrument manufacturers to improve on existing technology, and develop new, more accurate and precise measurement techniques,” he said.

Jennifer Krupka, a Senior Manager in Process Development for CSL Behring’s R&D team in Marburg, Germany, agreed. While she does not expect to notice changes in her daily routine just yet, it is still “a big step for science,” she said. “Using natural constants is the basis for high-precision measurements in the future, all over the world.”

Regardless of any immediate impact the redefinitions will have on their work, scientists agree that the changes were necessary. Ibrahim El Menyawi, a Process Development Director in Bern, Switzerland, listed several reasons he supports the redefinition of the kilogram.

“The mass of the original kilogram stored in Paris is not stable and it is impossible to quantify this instability,” he said, adding that the fact that this important reference material is only available at one laboratory in Paris was also a problem. He also said the new definition of the kilogram is not susceptible to damage or theft, unlike Le Grand K, no matter how well that shiny metal cylinder is guarded.