How much do you buy ~ and how is that quantified ? – in Kilogrammes
??
One is bound to ask – ‘what’s in a name ?’ ~ a rose by anyother
name would smell as sweet ! .. .. before
you proceed further – have you heard of ‘Saint-cloud’ ?- it is a commune in the western suburbs of Paris, France. It is known to
be one of the wealthiest towns in France. The town is named after Clodoald,
grandson of Clovis, who is supposed to have sought refuge in a hamlet on the
Seine near Paris, then named Novigentum .. .. wonder what its relevance here !!
Do you love travel by train ? - ~ Railways, the Nationalised
Career has a statue and does carries animals too .. .. the Railways
responsibility as a carrier is as per Indian Railways Act 1989. For loss or damage to goods carried as cargo
– Railways is responsible – however, where the value of the cargo is not
declared to carrier and %age charge is
not paid; the monetary liability of the railway has been limited to a measly
Rs.50/- per kilogramme.
The
kilogram or kilogramme (symbol: kg) is the base unit of mass in the
International System of Units (SI). Since 20 May 2019,
it has undergone a quantum change is the subject matter of this post ! The kilogram is a unit of mass, a property corresponding
to the common perception of how "heavy" an object is. Mass is an
inertial property; that is, it is related to the tendency of an object at rest
to remain at rest, or if in motion to remain in motion at a constant velocity,
unless acted upon by a force.While the weight of an object is dependent
on the strength of the local gravitational field, the mass of an object is
independent of gravity, as mass is a measure of the quantity of matter. Because
at any given point on Earth the weight of an object is proportional to its
mass, the mass of an object in kilograms is usually measured by comparing its
weight to the weight of a standard mass, whose mass is known in kilograms,
using a device called a weighing scale. The ratio of the force of gravity on
the two objects, measured by the scale, is equal to the ratio of their masses.
The
gram, 1/1000 of a kilogram, was provisionally defined in 1795 as the mass of
one cubic centimetre of water at the melting point of ice. The final kilogram,
manufactured as a prototype in 1799 and from which the International Prototype
Kilogram (IPK) was derived in 1875, had a mass equal to the mass of 1 dm3 of
water under atmospheric pressure and at the temperature of its maximum density,
which is approximately 4 °C.The kilogram is the only named SI unit with an SI
prefix (kilo) as part of its name. Until the 2019 redefinition of SI base
units, it was also the last SI unit that was still directly defined by an
artefact rather than a fundamental physical property that could be
independently reproduced in different laboratories. The IPK is rarely used or
handled. Copies of the IPK kept by national metrology laboratories around the
world were compared with the IPK in 1889, 1948, and 1989 to provide
traceability of measurements of mass anywhere in the world back to the IPK.
With the definition of the ‘kilogram’ getting a global,
technical makeover, textbooks — from those used in schools to ones recommended
by engineering colleges in India — are set to undergo an update.Until
Monday [20.5.2019], the kilogram derived its provenance
from the weight of a block of a platinum-iridium alloy housed at the
International Bureau of Weights and Measures in France. All other prototypes that served as national reference
standards, including the one at New Delhi’s CSIR-National Physical Laboratory
(NPL), were calibrated to it. No longer.On May 20, the kilogram joined
other standard units of measure such as the second, metre, ampere, Kelvin, mole
and candela that would no longer be defined by physical objects.
The
measures are all now defined on the basis of unchanging universal, physics
constants. The kilogram now hinges on the definition of the Planck Constant, a
constant of nature that relates to how matter releases energy.The kilogram isn't a thing anymore. Instead, it's an
abstract idea about light and energy.As of today (after May 20),
physicists have replaced the old kilogram — a 130-year-old, platinum-iridium
cylinder weighing 2.2 pounds (1 kilogram) sitting in a room in France —— with
an abstract, unchanging measurement based on quadrillions of light particles
and Planck's constant (a fundamental feature of our universe).
In
one sense, this is a grand (and surprisingly difficult) achievement. The
kilogram is fixed forever now. It can't change over time as the cylinder loses
an atom here or an atom there. That means humans could communicate this unit of
mass, in terms of raw science, to space aliens. The kilogram is now a simple
truth, an idea that can be carried anywhere in the universe without bothering
to bring a cylinder with you.And still...so what? Practically speaking, the new
kilogram weighs, to within a few parts per billion, exactly as much as the old
kilogram did. If you weighed 93 kilograms (204 pounds) yesterday, you'll weigh
93 kilograms today and tomorrow. Only in a few narrow scientific applications
will the new definition make any difference.
That
cylinder in France would weigh much less if you brought it to the moon, and
even a tiny bit more or tiny bit less if you brought it to other parts of the
Earth. Not that reference any longer !It's not the easiest thing to stick on a
scale. But, as an idea, it's a lot more portable than a cylinder of
platinum-iridium alloy.What was 1 kg earlier is still 1 kg today. If you had weighed 80 kgs a week before, you
would not otherwise weight less or more than that. You would be buying the same amount of
brinjals @ 1 kg or 1 kg or rice. All
that has changed is the definition, for the sake of accuracy. A mass measured as 1 kg earlier would have meant
1 kg, plus or minus 15-20 micrograms. Using the new definition, a mass measured
as 1 kg will mean “1 kg, plus or minus 1 or 2 nanograms”.
For
commoners like us, life has not changed at all – so we would continue to buy or
measure anything with the same kilogram though there appears a quantum change
in its definition.
With
regards – S. Sampathkumar
21st
May 2o19.
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