Kilogram Defined facts
While investigating facts about Kilogram Defined By Artifact and How Is The Kilogram Defined In 2018, I found out little known, but curios details like:
The International System of Units is expected to receive its first overhaul since 1960 in November 2018 - changing the kilogram, ampere, kelvin, and mole to be defined by observable constants - thus making SI wholly derivable from natural phenomena as originally envisioned
how is a kilogram defined?
The kilogram is currently defined as the mass of a platinum-iridium cylinder called the International Prototype Kilogram, which was made in 1879 and is stored in a special vault in France. There exist several dozen official replicas, also called prototypes.
In my opinion, it is useful to put together a list of the most interesting details from trusted sources that I've come across. Here are 24 of the best facts about How Was A Kilogram Defined Prior To 2019 and How Is One Kilogram Defined I managed to collect.
what is a kilogram defined as?
-
The world’s roundest object, a silicon-28 atom sphere, was created to perfectly define the weight of a kilogram. These spheres are so precisely round that if they were the size of the Earth, there would only be a 3-5 meter difference between Mount Everest and the Mariana Trench.
-
The definition of grams and kilograms have been flipped; the kilogram is the SI unit of mass, and the gram is defined as 1/1000th of a kilogram.
-
One litre of liquid water has a mass of almost exactly one kilogram, because the kilogram was originally defined in 1795 as the mass of one cubic decimetre of water at the temperature of melting ice.
-
The kilogram is still officially defined by a platinum-iridium cylinder made in 1879.
-
The kilomole was introduced to define larger sample units, which is the number of entities in twelve kilograms of carbon.
-
The kilogram was redefined on May 20th, 2019. Defined instead as a mathematical concept without the reliance on the physical object known as 'The Big K'
-
The Mendenhall Order of 1893, which defined the US yard and pound in relation to the standard metric metre and kilogram. The reason was that the metric standard measures were more reliable, so today US imperial measures are backed by the metric system
-
The International Bureau of Weights and Measures redefined the units of the metric (SI) system earlier this year. For mass they redefined the Planck Constant, then redefined the kilogram in terms of this newly defined constant.
-
The Kilogram is defined by a lump of platinum in Paris and if its mass changes, the kilogram changes.
-
Since the Mendenhall Order of 1893, the USA has defined the standard mass of a pound by its equivalent mass in kilograms.
What is true about kilogram defined?
You can easily fact check it by examining the linked well-known sources.
The pound is legally defined by the kilogram not as mass of its own
The kilogram is defined by the world's roundest object. - source
Since 1959 yard and pound are defined by meter and kilogram. - source
A kilogram is defined by the mass of a platinum object called the international prototype kilogram. This object literally defines the kilogram.
Since 1875, the exact weight of a kilogram has been defined by the International Prototype of the Kilogram, a cylinder that sits locked in an environmentally regulated vault outside Paris. Every 40 years, it's removed and compared to a half-dozen copies around the world - source
When was the kilogram defined?
The worlds roundest object is used for defining a kilogram and it is madeout of a single crystal!
How is the kilogram now defined?
The pound is fundamentally defined by a quantity of kilograms. In short, it is useless.
The worlds roundest object was made for defining a kilogram and it is made out of a single crystal!
The kilogram is the only SI unit defined by a physical object, that is currently in a climate controlled vault under three bell jars in the International Bureau of Weights and Measures in the outskirts of Paris. It has not been defined as the mass of a litre of water since 1889.
Until recently, the kilogram was defined by the "International Prototype Kilogram" (IPK) , a platinum-alloy cylinder made in 1889. From May 2019, a Kibble balance was used to link it to Planck's constant (because the weight of the IPK was changing subtly over time).
Until TODAY 1 kilogram was defined by "the big K", an iridium platinum cylinder conserved in France
