A kilogram (kg) is the primary unit of mass in the metric system and equals 1,000 grams.
The kilogram’s standard hasn’t changed in 129 years – that will soon change! On Friday, scientists at the General Conference on Weights and Measurements decided to redefine it by linking it to an essential constant from fundamental physics.
Weight
A kilogram (kg) is the basic unit of weight in the metric system, equal to 1,000 grams. It serves as the reference standard for other measurements, including mass, and provides scales with an easy reference when taking measurements of your body weight. Scientists and engineers worldwide utilize this standardized system of measures when working in these disciplines.
Recently, all weights and measures worldwide have been defined by one puck-shaped object, the International Prototype Kilogram (IPK), kept by the International Bureau of Weights and Measures in Sevres, France. To ensure accurate weighing worldwide, other masses could be directly compared against these IPKs, but on Friday, scientists from around the globe voted to redefine it using natural constants instead.
Redefinition has been an impressive and lengthy endeavor that spans decades. To determine the value of a kilogram, scientists must accurately measure a constant known as the Planck constant; its exact value has a tight margin of error that requires precise measuring techniques.
Scientists have employed an incredibly complex machine known as the Kibble balance to observe a small piece of platinum-iridium to achieve this. Multiple laboratories worldwide were required to cooperate to complete this intricate task successfully, making redefining a kilogram lengthy.
“Kilo” and “pound” are often interchanged terms. Under the metric system, “kilo” refers to one thousandth, or 103. Its root word in Greek was chilioi – meaning thousand. English uses different terminology: the imperial system uses 0.45359237 kilograms while the US customary uses an avoirdupois pound for food measurement purposes in general use in both countries.
Measurement
One kilogram is the universal unit of weight measurement in the metric system. Most countries utilize this measurement system; one kg equals 1,000 grams in its current iteration. Countries using either Imperial or United States Customary systems still employ kilograms equaling about 2.2 pounds (1 pound equals 16 ounces).
Scientists have long laid the groundwork for an alternative definition of the kilogram. With an ever-increasing demand for precise measurements across fields such as measurement science, device manufacture, material science research and testing, pharmaceutical R&T testing, and environmental monitoring demanding accurate results down to millionths of a gram or less measurements, scaling these up increases uncertainty significantly – so replacing physical objects defining kilogram with their digital equivalents allows these and three other base units to be defined with unprecedented precision.
Redefining the kilogram has been a massive undertaking requiring decades of hard work. First, scientists had to find ways of accurately measuring the Planck constant to provide an anchor point for their new definition of kilogram – something NIST and other labs worldwide have accomplished using innovative technology developed over time.
Scientists had to discover an accurate way of correlating the measured Planck constant with its current accepted value of one kilogram, which proved challenging given all the factors affecting mass. Some elements can’t be reckoned with as much precision.
NIST has developed the Kibble balance, an instrument capable of measuring light speed and the Planck constant with extreme accuracy. BIPM has employed this device to calibrate their primary 1 kg standards and replicated it in other labs worldwide as part of an international effort to establish a new global kilogram standard.
Conversion
A kilogram (k) is the unit of measurement for weight or mass and equals approximately 2.2 pounds, although sometimes also known as a kilogram.
Calculators make it simple and accurate to convert kilograms to pounds or vice versa, using conversion factors as necessary to get an approximate result. An element is used to cancel out original units while adding in any others that might be of interest; choose one as close to its actual value as possible to ensure the most precise results possible.
Converting kilograms to pounds can be confusing because different countries use these units of measure; imperial pounds and metric kilograms represent various length measures. To help make understanding these differences simpler, conversion tables provide helpful resources online that offer conversion factors for different kinds of units.
Another kilogram conversion method uses the metric prefixes: one gram equals one kg, and 1000 grams equals 10 kg. When discussing smaller mass units, you may also use atto, mili, and micro prefixes.
Apart from kilograms and grams, there are other units of weight measurement, such as ounces and tons. Pounds are standard units used within the United States customary measurement system and Imperial system; an avoirdupois pound equals 0.45359237 kilograms.
The kilogram used to be defined by its weight on a metal cylinder called the International Prototype Kilogram (IPMK). Still, this physical artifact wasn’t exceptionally stable. In 2019, a more reliable atomic standard using the Planck constant and other physical constants will occur – making for more reliable measurements worldwide by scientists and consumers alike.
Usage
A kilogram (kg), commonly referred to as kilogram and used within the SI (International System of Units), is a unit of mass used by international systems of units. This SI base unit measures 100 decagrams or 1000 grams, abbreviated as kg in everyday life for convenience when measuring food, human weight, or other things; this popular mass measurement is used globally for commerce transactions.
Kilograms are the next higher level of measurement after grams, used for weighing medium to heavy items such as food and fruit/veggies. Their name comes from the Greek word khilioi, meaning thousands; hence, the use in English and places names like Kilimanjaro or Kigali.
Utilizing the kilo when measuring food can have advantages when traveling in countries using the metric system. A kilo is more accurate because it measures weight more precisely and is more widely accepted worldwide – making it useful when comparing prices in various nations.
Kilograms play an essential part in science and engineering. One of three fundamental SI base units – along with meters and candela – changing its definition could alter them all, making its accuracy essential.
These examples were automatically chosen from various online sources to demonstrate the current usage of the word ‘kilo.’ They may or may not reflect the views or endorsement of Merriam-Webster and its editors.
