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Killing the kilo: scientists discuss a metric milestone at a cool talk

TIFR’s scientists weigh in on the end of an era when physical objects stood for prototypes in the metric system, at Sunday’s Chai and Why?

art and culture Updated: Sep 29, 2017 19:11 IST
Amanda D’Souza
Amanda D’Souza
Hindustan Times
Kilogram,International Prototype Kilogram,IPK
How will the departure of the International Prototype Kilogram tip the scales for us?(© Royalty-Free/CORBIS)
Chai and Why?: a session about a change in the metric system
  • Where: Prithvi Theatre, Juhu
  • When: Sunday, October 1, 11 am
  • Contact: 097571 57795
  • Entry is free

How much sugar is in my cola? How much can I stuff into hand luggage on my next vacation? Most of us go through life, measuring, counting and relying on the metric system without even knowing it.

Yet, this simple decimal-based system has long been fraught with complications.

Since 1889, a small cylinder, paradoxically known as Le Grand K, has been the standard against which man has defined the kilogram. This platinum-iridium cylinder, also called the International Prototype Kilogram (IPK), is housed in a bell jar filled with filtered laboratory air and stored in a vault outside Paris. It enjoys the security only high-ranking government officials can boast of.

Why the fuss? So that the weight of this cylinder remains a constant 1 kilo. But despite these measures, pollution and contamination is inevitable – all it takes is a film of dust to change the mass. So scientists have long hoped to retire Le Grand K and use a definition based on a fundamental constant of nature – something more practical and accessible. Their wish comes true next year.

How will this tip the scales for us? Amol Dighe, a theoretical physicist at the Tata Institute of Fundamental Research, offers some answers at their monthly Chai and Why? sessions aimed at simplifying science for the common man.

Measurement is one of the many ways in which physics sneaks into daily life. ( AP )

Chai and Why? has the casual vibe of a neighbourhood adda (and serves chai, of course). At Sunday’s session “Goodbye Mr.Kilogram”, Dighe will weigh in on the departure of the IPK and leave everyone wiser but not sadder about the impact of this change.

Feel free to ask questions after the audio-visual presentation. “Measurement is one of the many ways in which quantum mechanics sneaks into daily life. Even buying a kilo of veggies involves calculations that have a basis in physics,” says Dighe. “The aim of this redefinition is have a unit so precise and constant that it will endure over time and space,” says Dighe.

Will cola have less sugar? Will you be able to sneak in a heavier bag on the flight? Not really. But there will be changes, just weight and watch.

First Published: Sep 29, 2017 19:11 IST