Measuring the importance of World Metrology Day (May 20)

by Joseph Fuehne, director, Purdue College of Technology at Columbus

May 20 is observed annually around the world as World Metrology Day and commemorates the anniversary of the signing of the Metre Convention in 1875. This treaty provides the basis for a coherent measurement system worldwide. Because the Purdue College of Technology at Columbus has a well-equipped metrology lab that serves as a resource for students and local industry in our region and state, we will be celebrating World Metrology Day.

Most of us don’t recognize the importance that metrology plays in our lives. First of all, it has nothing to do with the weather. Metrology is the science of measurement, and most of us rely on measurement devices every day. We make decisions based on measurement results, such as pushing the brake pedal when the speed is over the limit or cutting down on sweet food if our blood sugar level is too high. The price of much of what we buy is calculated from measurements — electricity, water, food, fuel, to name a few.

When you buy gas, how do you know for sure that you’re actually receiving the volume of gas indicated on the pump? Each state has a division or bureau of weights and measures. In Indiana, the Weights and Measurements program is under the auspices of the Indiana State Department of Health. Every county in Indiana has a weights and measures inspector whose job is to ensure that when a gas pump indicates that it has pumped 12.4 gallons of gas that it actually has pumped that amount. Every gas pump in the state should have a sticker from the Indiana Weights and Measures division that indicates the last time it was calibrated and approved. These checks should occur on a regular basis, usually annually, but possibly more frequently especially if there are complaints. With the rising costs of gasoline, this service by the state is critical. Each country also has a National Measurement Institute (NMI) and in the USA that official organization is the National Institute for Standards and Technology (NIST).

However, there are other places where measurement impacts our daily lives. Grocery stores often sell vegetables, fruits, meats, and other produce by weight. All check out scanning stations have scales that weigh the bananas or apples you’re buying and then the store associate will code that information into the register to determine the overall price. Again, these balances must be calibrated frequently to ensure that they’re weighing objects accurately and consumers are being charged the proper amount.

Health services are another area of frequent measuring. Doctors, nurses and hospitals depend on devices that measure blood pressure, cholesterol, body temperature, blood sugar, and weight as well as many other more sophisticated measurements. These measurements are critical to the good health and well being of consumers. In the middle 1970s, a hospital in Ohio failed to calibrate an instrument that measured radiation being applied to cancer patients; over 400 patients received significantly more radiation than was necessary. This is just one example, albeit a tragic one, where measurement mistakes have been significant.

In the manufacturing industry, there’s a common saying that “If it can’t be measured, it can't be built.” Manufacturing companies rely heavily on accurate and reliable measurement systems to design, inspect, and build their products. Many of these systems, however, are measuring distances at the nanometer level, smaller than the diameter of a human hair. Metrology is critical to our technological advancement but is seldom recognized by the general public.

The Purdue College of Technology at Columbus has begun to offer classes and provide services to local industry in metrology. The metrology lab at the Advanced Manufacturing Center of Excellence is climate controlled (20°C ±0.5° and less than 35% humidity) and has a wide range of tools for dimensional and mass measurement. For more information about the lab,  contact Joe Fuehne at 812-348-2040 or

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