Category Archives: Metric Education

Asimov and Metric Prefixes

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Isaac Asimov (1920-1992)

By The Metric Maven

The late Isaac Asimov (1920-1992) was a great promoter of the metric system. In the early 1960s Dr. Asimov wrote an essay about the metric system entitled Pre-Fixing It Up. The essay appears to have been inspired by the official addition of new metric prefixes in 1960. Some of the essay shows its age, but Asimov makes an observation about the metric system which still seems lost on most people:

All other sets of measurements with which I am acquainted use separate names for each unit involving a particular type of quantity. In distance, we ourselves have miles, feet, inches, rods, furlongs, and so on. In volume, we have pecks, bushels, pints, drams. In weight, we have ounces, pounds, tons, grains. It is like the Eskimos, who are supposed to have I don’t know how many words for snow, a different word for it when it is falling or when it is lying there, when it is loose or packed, wet or dry, new-fallen or old-fallen, and so on.

We ourselves see the advantage in using adjective-noun combinations. We then have the noun as a general term for all kinds of snow and the adjective describing the specific variety: wet snow, dry snow, hard snow, soft snow, and so on. What’s the advantage? First we see a generalization we did not see before. Second, we can use the same adjectives for other nouns, so that we can have hard rock, hard bread, hard heart, and consequently see a new generalization, that of hardness.

The metric system is the only system of measurement which, to my knowledge, has advanced to this stage.

Asimov makes a point in the 1960s which appears to be completely absent from contemporary metric advocacy discussions. The metric prefixes themselves provide an intuitive set of relative magnitudes, expressed in literary form. People do not generally realize this because of the dismal manner in which “scientific journalists” present weights and measures in the media. I wrote a guest blog on the penetration of metric prefixes into our culture, but they only are vaguely understood, and their monotonic relationship is not clearly articulated.

There is only one technical area with which the public deals that has slowly introduced each metric prefix such that people have an idea of their relative magnitudes. That area is computers. In the early days of computing, a computer such as the Timex Sinclair 1000 came with about 2K of memory. That is, it has approximately 2 Kilobytes of memory. Memory escalation had begun and the Commodore 64 had—well—64 Kilobytes of random access memory (RAM). Soon computers would have Megabytes of RAM. The computer I’m currently using to write this essay has 2 Gigabytes of RAM. The use of the metric prefixes to describe computer memory has been a slight kludge as computer memory is in multiples of two. A Kilobyte is actually 1024 bytes instead of 1000 bytes as the metric prefix implies. There is an attempt to introduce binary name versions called the kibi, mebi, gibi and so on, which correspond to the actual metric prefixes, but exactly describe the number of bytes.

Metric prefixes have long been used to approximately count up all the ones and zeros available in computer memory, or on a disk drive. The RAM of a typical computer has increased from Kilobytes, to Megabytes, to Gigabytes. One knows that a file which is in the Kilobyte range is easily emailed. A file which is 1-2 Megabytes is pushing the email envelope a bit, and 10 Megabytes is a really large file to attach to an email. One would not even consider sending a 1 Gigabyte file, it is immediately apparent from the prefix that it is untenable.

As Asimov points out, the metric prefixes act like adjectives. Email attachment file sizes can be seen as small (Kilobytes), large (under 4 Megabytes), and too large (Gigabytes).

Computers use disk drives to store digital files.  5 1/4 inch floppy drives increased from 360 kilobytes to 1.2 megabytes. The 5 1/4 inch floppy drive was replaced by the 90 mm (~3.5″) floppy which held about 1.44 megabytes. Hard disk drives (HDD) with many Megabytes of space were introduced to the consumer. As time went on, Gigabyte sized hard drives were introduced. When compared with Megabyte sized drives, they seemed almost limitless in size. Currently 1-2 Terabyte drives are commonly available. The Greek roots of the prefixes are descriptive. Megas means “great,” gigas is “giant” and terras is “monster.”  Indeed a Terabyte drive is monstrous in size—at least as of this writing.

The problem is that only in the computer industry have we been inculturated with the metric prefixes. As I pointed out in an earlier essay, I was not pleased that the producers of Cosmos chose to use Kilometers, light-years and astronomical units to describe celestial distances. Dr. Asimov encouraged metric usage in astronomy over forty years ago. He begins with the meter, then describes the Kilometer in terms of distances in Manhattan, “…a kilometer would represent 12 1/2 city blocks.” He moves on to the Megameter:

This is a convenient unit for planetary measurements. The air distance from Boston, Massachusetts, to San Francisco, California is just about 4 1/3 megameters. The diameter of the earth is 12 3/4 megameters and the circumference of the earth is about 40 megameters. And finally, the moon is 380 megameters from the earth.

Passing on to the gigameter, ….this comes in handy for the nearer portions of the solar system. Venus at its closest is 42 gigameters away and Mars can approach us as closely as 58 megameters. The sun is 145 gigameters from the earth and Jupiter at its closest, is 640 gigameters distant; at its farthest, 930 gigameters away.

There is no need for Asimov to have qualified the Gigameter as only being “handy for the nearer portions of the solar system.” This is a pre-Naughtin’s Laws view of the metric system. The Gigameter is completely useful for describing the distance to Pluto and the position of the Voyager 1 and 2 spacecraft. Asimov continues:

Finally, by stretching to the limit of the newly extended metric system, we have the terameter…this will allow us to embrace the entire solar system. The extreme of Pluto’s orbit, for instance is not quite 12 terameters.

Two factors that Asimov did not foresee was that Neil deGrasse Tyson would “kill Pluto” and the introduction of Naughtin’s 3rd Law: Don’t Change Measures in Midstream. The extreme of Pluto’s orbit quoted in Asimov’s essay is 12 000 Gigameters. If the Australian construction industry can handle this large of a number in millimeters, I’m sure astronomers can muddle through with it in Gigameters.

One cannot fault Asimov for not pushing matters further. It would not be until 1991 when enough metric prefixes would be added to encompass the entire observable universe.  Asimov does realize the limitations of light-years and parsecs (3.2 light years):

Even  these nonmetric units err on the small side. If one were to draw a sphere about the solar system with a radius of one parsec, not a single known star would be found within that sphere. The nearest stars, those of the Alpha Centauri system, are about 1.3 parsecs away.

The current version of the metric system has no problem describing the macroscopic universe. Here is a table from an earlier essay on the subject:

click to enlarge

The overall point is that if the metric system was completely adopted in the US without dilly-dallying, we would use the metric system, and its appropriate prefixes, to describe all important scientific discoveries and ideas. Children would grow up memorizing metric prefixes (without the prefix cluster about unity) as earlier children committed multiplication tables to memory. This exclusive metric ecosystem would soon provide  a reinforcing context for the relative sizes of the metric prefixes, and make the public as well as people in technical vocations, much more numerate. Astronomy texts would use metric to describe distances, and only mention light years as a gee-whiz! metaphorical supplement to actual measurement units.

Dr. Asimov died in 1992, just after the new set of metric units from yocto to Yotta were adopted. They describe the world which engineering and science encompass at this time. It is sad that the gentle doctor has been gone for over 20 years, and we are no closer to adopting metric units for everyday engineering and science, let alone in our public news media. Dr. Asimov expressed his frustration that no one was listening to his appeals for the metric in the early 1960s in his essay Forget It!. The US has continued to ignore the metric system for over 50 years since that essay first appeared. Will metric adoption take 200-300 more years to occur in the US? I don’t know. What I do know is I don’t have time to wait around that long, and neither did Dr. Asimov.

Isaac Asimov’s birthday was on January 2.

If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.


The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.


The third book is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.

Taking The Metric Fifth

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By The Metric Maven

Bulldog Edition

Last year I attended a post-Thanksgiving social function. One of the hosts was busy in the kitchen creating some manner of confection with bourbon in it.  I was suddenly sought out as the resident measurement person and this conversation occurred:

Host: “How much is a fifth of whiskey?”

MM: “There is no such thing anymore, it’s 750 mL. I believe it used to be one-fifth of a gallon.”

The Host clearly saw my answer as completely unsatisfactory, apparently very difficult to believe, and asked to borrow a smart-phone so he could look on the internet. After some conversation with others and my directly asking, he indicated I was right. It just seemed like too much liquor to put into the recipe.

The fifth is a surprisingly strange volume—even for US Ye Olde English Units. The fifth was equal to 1/5 of a US gallon which is equal to 4/5 of a quart which is also equal to 25 3/5 fluid ounces which is 757 mL.

Whenever my friend Lapin is confronted with something he said in the past which after some reflection appears incoherent, he generally states: “I don’t know, I must have been drunk at the time.” The spirits industry apparently wasn’t when they chose the fifth. According to Amy Richards Krumich, who for a short time wrote a metric blog called Penny Wise and Pound Foolish, the origin of The Fifth is thus:

That size [750 mL] was chosen [by Europe and the US] because it contained approximately the same volume as the “American Fifth” (a fifth of a gallon) whether it was wine or hard spirits. The fifth had been invented by the spirits industry many years before to avoid being taxed, since taxes were assessed for quarts or larger volumes of wine or spirits.

So the quantity was invented to avoid liquor taxes? That seems likely.

One of the strangest occurrences in the 1970s, was that one industry apparently didn’t get the memo that the metric system in the US is very, very, very voluntary. It was the hard liquor and wine industry. This is an amazing singularity, and is offered constantly as an example that we are “going metric soon” because the alcohol manufacturers have done so. Unfortunately US metrication is always a Friedman Unit away, but well-meaning metric enthusiasts cite it as evidence of current change. In his 2004 book The United States of Europe T.R. Reid states on page 5:

Because the united Europe is the world’s largest trade market, it is the “Eurocrats” in Brussels, more and more, who make the business regulations that that govern global industry. There’s a reason why the quintessential American whiskey, Kentucky bourbon is sold today in 75 cl bottles. It’s not because American consumers suddenly demanded to sip their sour mash by the centiliter

Later on page 233:

No matter how efficient and and logical metrics might be, we still prefer our inches and feet, ounces and pounds, yards and miles. But American food and drink labels today are going metric. You can’t buy a “fifth” (that is, a fifth of a gallon) of American Whiskey anymore; all liquors are sold by the centiliter today, because that’s how the European market demands it. Instead of a “fifth” the standard bottle now is 70 or 75 centiliters, which turns out to be a few sips short of a fifth of a gallon. It is because of the European regulatory influence that Americans routinely buy 2-liter bottles of Coca-Cola….”

T.R. Reid like other US citizens knows about as much about the metric system as most Americans do about cricket. Centiliters! Seriously? Milliliters are what are used in enlightened metric countries—like Australia. The Eurocrats in Brussels forced the US into metric booze?–and two liter bottles of soda?

Here is what Wikipedia states about the “Metric Fifth”:

During the 1970s, there was a push for metrication of U.S. government standards. In 1975, the Bureau of Alcohol, Tobacco and Firearms, in cooperation with the Distilled Spirits Council of the United States, proposed six metric-standard bottle sizes to take effect in January 1979 and these standards were incorporated into Title 27 of the Code of Federal Regulations.[7][8] These sizes are 50, 100, 200, 375 (355 for cans), 500 (until June 1989), 750, 1000, and 1750 mL.

The mystery is that this change occurred at all. The actual change for liquor occurred in 1979, at the height of the “US faux-metric-conversion.” It is my understanding that the European Union was founded in 1993. So Brussels “forced” 750 mL bottles of Whiskey on the US approximately 14 years before the EU was founded? The two-liter bottle was introduced by Pepsi in 1970—and seemingly has zero to do with any proclamations from Brussels at the end of the 1960s—unless those are some supernaturally powerful Eurocrats!

In recent years I’ve been pleased to see bottles of soda which are 500 mL and 1 liter, but I’ve also seen pints, quarts and numerous variations of Ye Olde English proliferate with them. It seems very likely this mixture of odd sizes is somehow used to “profit from the yardstick.” If they were all in metric, and in milliliters, there would be no wiggle room. You would see the difference between a 300, 350 and 355 mL can of anything immediately and easily compute the price per mL. Market Darwinism embraces the proliferation of measurement units, as it has throughout history.

There are many aphorisms about the metric system in the US that I believe cause complacency. One statement is “We’re over 50% metric in the US.” I’ve never been able to trace down any reference, or any study upon which this assertion could “hold water.” The fact that booze is sold in metric, and that we have two-liter bottles is also offered as contemporary evidence of change—every decade since the change occurred. This is change which actually occurred over 35 years ago for liquor and 44 years ago for two-liter bottles. It’s time to face up to the fact that metric usage in the US is stagnant, and waiting for metrication to magically happen without government intervention is a fools errand. Asserting stagnation is actually alteration only causes procrastination. Waiting doesn’t produce change, nor does quaffing a metric drink of alcohol move us one millimeter closer to a metric US. A person who asserts otherwise?—-“must have been drunk at the time.”

Related essay:

The Singular Beverage Experience

If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.


The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.


The third book is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.