Metrology I – Really Big and Really Small Numbers
??????????? For many years I taught for two weeks in Humanities 1, a course called “On Being Human.”? There were eight two-week segments.? A faculty member from History taught, “Humans as Revolutionaries.”? Someone from the English with a specialty in literature taught, “Humans as Myth-makers.”? My colleague from the Art department taught, “Humans as Creators.”? And I taught “Humans as Scientists.”? It was really fun because you had all of the fun of teaching – interacting with students – but had very little of the dreary grading and evaluation part; I called it a drive-by teaching.? But I took the responsibility seriously – I viewed myself as representing the entire discipline and perhaps the most successful of all human activities.
??????????? In the first lecture I always made the claim that “science has fundamentally changed the human condition.”? I showed a graphic with life expectancy and infant mortality in 1900 versus 2000.? Life expectancy doubled and infant mortality plummeted.? What made the difference I would ask?
??????????? Science
??????????? The other point that I made as quickly as possible: science deals in really big numbers and really small numbers.? These quantities fall outside of daily experience, unless your daily experience is being an astronomer, physicist, or chemist.?? And I made the point that humans developed, and continue to develop, methods of measurement that have increasing precision and accuracy.? There is an entire field covering the science of measurement called metrology.? And like all science, this changes with new innovations – including some introduced relatively recently.?
“An experiment is a question which science poses to Nature, and a measurement is the recording of Nature’s answer.”? - Max Planck
??????????? Most biotech companies will have a metrology department.? Quite a lot of the effort of the metrology department is keeping up the calibration of the instruments.? It is my experience that most of the people working in metrology were trained in the Navy – an endeavor where precise measurement has been required for navigation for several hundred years.? Also the American Society for Quality has a “Calibration Technician Certification” and I’ve incorporated that curriculum into our biotechnology program.? I tell students that they are way ahead, having completed multiple chemistry and math classes, since quite a lot of the test for the certification is the SI (metric) system, scientific notation (for very large and very small numbers), and what they called “engineering prefixes” – the prefixes used in the metric system.
??????????? Also I would be remiss if I did not mention the heart of metrology in the United States, the National Institute of Standards and Technology, NIST – located within the Department of Commerce.? NIIMBL, the National Institute for Innovation in the Manufacturing of Biologics falls under NIST jurisdiction, and I’ve met many people from NIST at conferences over the years.? The Department of Commerce is taking the lead, of all federal cabinet level departments, in coordinating activities by all agencies of the Federal government to promote a future bioeconomy.?? Accurate measurement is important for all areas of commerce – from the sale of meat to the dispensing of gasoline - as well as for science, and again, essential for the manufacturing of biotech products.?? ???
??????????? A friend of mine asked, “do you want to write a chapter on metrology for my book?”
??????????? “Sure.? I’ll start with the history of the metric system, and how it was born in the French Revolution and during a war with neighboring countries, and describe the work of Jean-Baptiste-Joseph Delambre measuring moving North from Paris to Dunkirk while Pierre-Fran?ois-André Méchain measured in a Southern route ending in Barcelona (as outlined in Ken Adler’s book The Measure of All Things).? And I’ll cover horology, the science of time, by telling the story of John Harrison and the usefulness of time to naval navigation (as outlined in Dava Sobel’s book Longitude).”
??????????? “History, eh?? Nevermind.”
??????????? OK, so you are stuck with the stories.??? ?
??????????? For measurement, all countries in the world use the Systeme Internationale, the SI system.? Most people know this as the metric system.
??????????? Americans think that we have a separate system, but we are fully metric.? The United States Customary System, referred to in my youth as the English system, is defined by the international metric measurement.? (An inch is defined as 2.54000000000000_ centimeters).? There are seven base units:? meter (linear distance), kilogram (mass), second (time), degree Kelvin (temperature), mole (amount of substance), ampere (current), and candela (luminosity).??
??????????? The international standards organization is the Bureau International des Poids et Mesures (the French invented the system, so take a central position).? In the United States it’s the National Institute for Standards and Technology.
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??????????? ?In the Humanities class I made the point that science deals in astronomically (literally) large numbers and extraordinarily and incomprehensibly small numbers.?
??????????? For a large number, I have students go through a calculation carried out on in the “What If?” books and on the website XKCD (that provides “serious scientific answers to absurd hypothetical questions”).??? They ask:
What would happen if you were to gather a mole (a base SI unit of measurement) of moles (the small furry critter) in one place?”??
?The point of the exercise is to emphasize just how enormous Avogadro’s number is:
This is the post 2019 number 602,214,076,000,000,000,000,000 or 6.02 X 10^23
??????????? This trillion, trillion is a really big number.?
??????????? Spoiler alert:? If you put a mole of moles on the surface of the earth we would be 80 kilometers deep in moles.? If you put a mole of moles in space, it would form a sphere a little bigger than the moon.? A mole represents a really big number.
??????????? And there is another interesting reason to discuss this unit:? the value recently changed, in 2019 – because of the change in the kilogram.? (But that’s a story for another time).? And another change occurred at another conference.? Every country sent representatives to the General Conference on Weights and Measures (CGPM) outside Paris and they voted to introduce four new prefixes to the International System of Units (SI).? The prefixes are to describe numbers bigger and smaller.? The CGPM added the prefixes ronna (10^27), quetta (10^30), ronto (10^-27) and quecto (10^-30). Earth weighs around one ronnagram and an electron’s mass is about one quectogram. ?
??????????? Like many people, I had to learn the larger prefixes to keep up with computer speed and computer memory.? The first computers used kilohertz and kilobytes.? I remember paying $400 for a 40 megabyte hard-drive.? The computer that I’m working on measures its memory in terabytes – a prefix that I didn’t know until it became important.?
??????????? It’s really the large amount of data generated per year that is effecting the change and at the conference the large numbers were treated as more important than the small numbers.? The annual volume of data generated globally currently is in the zettabyte range and is expected to reach the yottabyte range ?by the 2030s. On the small end there has historically been what’s called the yoctogram limit – the mass of protons and neutrons are in the yoctogram range and it didn’t seem like a measurement smaller than that would be useful very often.? But, an electron’s mass is about one quectogram and quarks are smaller than that. ?So perhaps that’s useful too.?
??????????? I regret that the international body of metrologists rejected one of the suggestions for 10^27. There was a proposal to make 1,000 yottabytes = 1 hellabyte. I liked that, because it’s a hella big number.?
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