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Posts Tagged ‘measurement

“A measurement is not an absolute thing, but only relates one entity to another”*…

 

kilogram

 

Until now, [the mass of the kilogram] has been defined by the granddaddy of all kilos: a golf ball-sized metal cylinder locked in a vault in France [a replica of which is pictured above]. For more than a century, it has been the one true kilogram upon which all others were based…

Made of a corrosion-resistant alloy of 90 percent platinum and 10 percent iridium , the international prototype kilo has rarely seen the light of day. Yet its role has been crucial, as the foundation for the globally accepted system for measuring mass upon which things like international trade depend.

Three different keys, kept in separate locations, are required to unlock the vault where the Grand K and six official copies — collectively known as ‘‘the heir and the spares’’ — are entombed together under glass bell-jars at the International Bureau of Weights and Measures, in Sevres on the western outskirts of Paris.

Founded by 17 nations in 1875 and known by its French initials, the BIPM is the guardian of the seven main units humanity uses to measure its world : the meter for length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the mole for the amount of a substance and the candela for luminous intensity.

Of the seven, the kilo is the last still based on a physical artifact, the Grand K. The meter, for example, used to be a meter-long metal bar but is now defined as the length that light travels in a vacuum in 1/299,792,458th of a second…

The metal kilo is being replaced by a definition based on Planck’s constant, which is part of one of the most celebrated equations in physics but also devilishly difficult to explain . Suffice to say that the update should, in time, spare nations the need to occasionally send their kilos back to Sevres for calibration against the Grand K. Scientists instead should be able to accurately calculate an exact kilo, without having to measure one precious lump of metal against another…

More of this weighty story at “The kilogram is changing. Weight, what?

* H.T. Pledge, Science since 1500

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As we muse on measurement, we might send well-calibrated birthday greetings to August Kundt; he was born on this date in 1839.  An astronomer-turned-physicist, he developed a method to measure the velocity of sound in gases and solids using a closed glass tube (now known as a Kundt’s Tube).

AugustKundt source

We might also spare a thought for another physicist, Niels Bohr; he died on this date in 1962.  A Danish physicist and philosopher, Bohr was the first to apply quantum theory to the problem of atomic and molecular structure, creating the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete, and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another– a model the underlying principles of which remain valid.  And he developed the principle of complementarity: that items could be separately analyzed in terms of contradictory properties, e.g., particles behaving as a wave or a stream. His foundational contributions to understanding atomic structure and quantum theory won him the Nobel Prize in Physics in 1922.

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“The heart of science is measurement”*…

 

In October 1958, Oliver R. Smoot (future Chairman of the American National Standards Institute) repeatedly laid down on the Harvard Bridge connecting Boston and Cambridge, Massachusetts, so that some of his Lambda Chi Alpha fraternity brothers could measure the entire length of the bridge in relation to his height. At 5 feet 7 inches tall, the bridge was found to be 364.4 “Smoots” long (plus or minus an εar). The prank quickly became the stuff of legend (to this day, graffiti on the bridge still divides it up into Smoot-based sections) until finally, in 2011, the word smoot was added to the American Heritage Dictionary, defined as “a unit of measurement equal to five feet, seven inches.”…

More exceedingly-specific units of measurement, and the stories behind them: “10 Ridiculously Precise Units of Measurement.”

* Erik Brynjolfsson

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As we quantify quantity, we might spare a thought for Richard Bevan Braithwaite; he died on this date in 1990.  A Cambridge philosopher who specialized in the philosophy of science, he focused on the logical features common to all sciences.  Braithwaite was concerned with the impact of science on our beliefs about the world and the appropriate responses to that impact.  He was especially interested in probability (and its applications in decision theory and games theory) and in the statistical sciences.  He was president of the Aristotelian Society from 1946 to 1947, and was a Fellow of the British Academy.

It was Braithwaite’s poker that Ludwig Wittgenstein reportedly brandished at Karl Popper during their confrontation at a Moral Sciences Club meeting in Braithwaite’s rooms in King’s. The implement subsequently disappeared. (See here.)

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“If something is there, you can only see it with your eyes open, but if it isn’t there, you can see it just as well with your eyes closed. That’s why imaginary things are often easier to see than real ones.”*…

 

In the age of GPS and Google Maps, it is hard to believe that maps can include places that don’t exist. But author Malachy Tallack argues that maps are as much “a cartography of the mind” as they are a way to figure out where we are. In his new book, The Un-Discovered Islands, Tallack takes readers on a journey to imaginary places—mythic islands, mapmakers’ mistakes, mirages, and outright hoaxes. [E.g., explorer Robert Peary discovered a continent that wasn’t there.]…

Some islands, like King Arthur’s Avalon, were pure legend. Others were mistakes or outright hoaxes.  Learn why some islands blur the line between life and death; how others have moved about on the maps; why we’re living in an era of un-discovery; and relatedly, why ancient mapmakers were afraid of blank spaces: “These Imaginary Islands Only Existed on Maps.”

* Norton Juster, The Phantom Tollbooth

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As we seek solid ground, we might spare a thought for Rear Admiral Sir Francis Beaufort, KCB, FRS, FRGS, MRIA; he died on this date in 1857.  A career naval officer and hydrographer, Beaufort devised, in 1806, a simple scale that coastal observers could use to report the state of the sea to the Admiralty.  Originally designed simply to describe wind effects on a fully rigged man-of-war sailing vessel, it was later extended to include descriptions of effects on land features as well.  Officially adopted in 1838 (and in use to this day), it uses numbers 0 to 12 to designate calm, light air, light breeze, gentle breeze, moderate breeze, fresh breeze, strong breeze, moderate gale, fresh gale, strong gale, whole gale, storm, and hurricane. Zero (calm) is a wind velocity of less than 1 mph (0.6 kph) and 12 (hurricane) represents a velocity of over 75 mph (120kph).

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Written by LW

December 17, 2017 at 1:01 am

“What gets measured gets done”*…

 

Goodhart’s Law: when a measure becomes a target, it cease to be a good measure.

In other words, if you pick a measure to assess people’s performance, then we find a way to game it..

More illustrated explication at Sketchplanations.

* one of many aphoristic echoes in the vernacular of a statement by William Thomson, the Scottish physicist also known as Lord Kelvin

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As we’re careful what we ask for, we might we might recall that it was on this date in 1864 that Oxford mathematician and amateur photographer Rev. Charles Lutwidge Dodgson– aka Lewis Carroll– delivered a handwritten and illustrated manuscript called “Alice’s Adventures Under Ground” to 10-year-old Alice Liddell.  The original (on display at the British Library) was the basis of Alice’s Adventures in Wonderland… which was published exactly one year later, on this date in 1865.

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“if we’re measuring the wrong thing, we’re going to do the wrong thing”*…

 

Money and markets have been around for thousands of years. Yet as central as currency has been to so many civilizations, people in societies as different as ancient Greece, imperial China, medieval Europe, and colonial America did not measure residents’ well-being in terms of monetary earnings or economic output.

In the mid-19th century, the United States—and to a lesser extent other industrializing nations such as England and Germany—departed from this historical pattern. It was then that American businesspeople and policymakers started to measure progress in dollar amounts, tabulating social welfare based on people’s capacity to generate income. This fundamental shift, in time, transformed the way Americans appraised not only investments and businesses but also their communities, their environment, and even themselves.

Today, well-being may seem hard to quantify in a nonmonetary way, but indeed other metrics—from incarceration rates to life expectancy—have held sway in the course of the country’s history. The turn away from these statistics, and toward financial ones, means that rather than considering how economic developments could meet Americans’ needs, the default stance—in policy, business, and everyday life—is to assess whether individuals are meeting the exigencies of the economy…

Eli Cook explains how America pioneered a way of thinking that puts human well-being in economic terms: “How Money Became the Measure of Everything.”

* “GDP is not a good measure of economic performance; it’s not a good measure of well-being.  What we measure informs what we do. And if we’re measuring the wrong thing, we’re going to do the wrong thing.”    – Joseph Stiglitz

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As we muse on metrics, we might spare a thought for Henry George; he died on this date in 1897.  A writer, politician and political economist, George is best remembered for Progress and Poverty, published in 1879, which treats inequality and the cyclic nature of industrialized economies, and proposes the use of a land value tax (AKA a “single tax” on real estate) as a remedy– an economic philosophy known as Georgism, the main tenet of which is that, while individuals should own what they create, everything found in nature, most importantly the value of land, belongs equally to all mankind.

George’s ideas were widely-discussed in his time and into the early 20th century, and admired by thinkers like Alfred Russel Wallace, Jose Marti, and William Jennings Bryan; Franklin D. Roosevelt sang his praises, as did George Bernard Shaw.  But with the rise of neoclassical economics, George’s star began to recede.  Still, more modern thinkers like Albert Einstein and martin Luther King were fans.

In a sequence that mimicked George’s arc of influence, it was George’s work that inspired Elizabeth Magie to create The Landlord’s Game in 1904 to demonstrate his theories; ironically, it was Magie’s board game that became in the 1930s (as recently noted here and here) the basis for Monopoly.

In 1977, Joseph Stiglitz showed that under certain conditions, spending by the government on public goods will increase aggregate land rents/returns by the same amount. Stiglitz’s findings were dubbed “the Henry George Theorem,” as they illustrate a situation in which Henry George’s “single tax” is not only efficient, it is the only tax necessary to finance public expenditures.

Henry George

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Written by LW

October 29, 2017 at 1:01 am

“Race does not stand up scientifically, period”*…

 

The genetic distance between some groups in Africa, such as the Fulani of West Africa (above) and the Hazda of Tanzania, is greater than supposedly racially divergent groups such as East Asians and Europeans.

If race categories were meant primarily to capture differences in genetics, they are doing an abysmal job. The genetic distance between some groups within Africa is as great as the genetic distance between many “racially divergent” groups in the rest of the world. The genetic distance between East Asians and Europeans is shorter than the divergence between Hazda in north-central Tanzania to the Fulani shepherds of West Africa (who live in present-day Mali, Niger, Burkina Faso, and Guinea). So much for Black, White, Asian, and Other.

Armed with this knowledge, many investigators in the biological sciences have replaced the term “race” with the term “continental ancestry.” This in part reflects a rejection of “race” as a biological classification. Every so-called race has the same protein-coding genes, and there is no clear genetic dividing line that subdivides the human species. Another reason for using the term “continental ancestry” in lieu of “race” is improved precision for locating historical and geographic origins when we look at the genome. Thus, continental ancestry allows for more genetically accurate descriptors. For example, President Barack Obama was not just the first socially “black” president. He was also the first (as far as we know) who has European and African ancestry.

In sum, racial categories now in use are based on a convoluted and often pernicious history, including much purposefully created misinformation.

It is a good time, then, to dispel some myths about genetic variation that have been promulgated by both the left and the right alike…

Setting the scientific record straight on race, IQ, and success: “What Both the Left and Right Get Wrong About Race.”

* Dalton Conley and Jason Fletcher

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As we hear Bob Marley sing “One love, one heart, let’s get together and feel all right,” we might recall that it was on this date in 1795 that the first (but still provisional) official standard “metre bar” was forged in Paris.  Made of brass, its length was one ten-millioneth of the northern quadrant of the Paris meridian.

In the aftermath of the French Revolution (1789), the traditional units of measure used in the Ancien Régime had replaced; the livre monetary unit was replaced by the decimal franc, and a new unit of length was introduced– the metre.

This first prototype was short by 0.2 millimeters because researchers miscalculated the flattening of the earth due to its rotation.  Still this length became the standard– replicated in platinum– until 1889, when new, more accurate measurements were used to create a new standard metre, that gained acceptance across the world.

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Written by LW

June 9, 2017 at 1:01 am

“The only lasting truth is Change”*…

 

A running tally of world population, plus telling (and similarly constantly-updated) statistics on government and economics, society and media, the environment, food, water, energy, and health, all derived from sources including the United Nations Population Division, the World Health Organization (WHO), the Food and Agriculture Organization (FAO), the International Monetary Fund (IMF), and the World Bank: Worldometers.

* Octavia E. Butler

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As we watch the world tick by, we might recall that it was on this date in 1923 that the Zero Milestone was dedicated just south of the White House at the north edge of the Ellipse, within President’s Park.  Intended as the initial milestone from which all road distances in the United States should be reckoned, at present only roads in the Washington, D.C. area have distances measured from it.

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Written by LW

June 4, 2017 at 1:01 am

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