Quick--how many inches in a mile?

Just 63,360 inches, didn't you know? Of course not, unless you can do the arithmetic: 1 mile equals 5,280 feet, multiplied by 12 (for 12 inches in every foot) for 63,360 inches.

Not so easy to remember, eh?

Try the metric system. It's an easy system based on 10, like this:

10 millimeters=1 centimeter

10 centimeters=1 decimeter

10 decimeters=1 meter

10 meters=1 decameter

10 decameters=1 hectometer

10 hectometers=1 kilometer

So how many centimeters in a kilometer? It's easy: 100,000. Once you have memorized the order, it's just a matter of multiplying 10a.

Most of the world uses the metric system, which was created in France in 1795. The people there had just overthrown their king and wanted an all new society, including measurements.

So they invented the meter: 1 ten-millionth of the distance from the North Pole to the equator. They divided it by 10s to get smaller units and multiplied it by 10s to get larger lengths.

Meanwhile the English speaking world--that's us--kept on using the old-fashioned measurements like the foot, the yard, and the inch. These developed separately, based on the only measuring device handy in the dim past--the human body.

1 yard--about the distance from the tip of the fingers to the nose.

So do thumbs multiply to feet which then multiply to give arm lengths which then multiply out to miles? Hardly. Miles were actually based on 1,000 pace lengths as marched by Roman soldiers, called milia passuum in Latin.

In America we measure weight in pounds and ounces. To this, the British add the stone, and say that someone weighs 12 stone when they mean 168 pounds.

The rest of the world doesn't worry about remembering how many ounces to the pound, or how many pounds to the ton, and whether you're talking about "avoirdupois weight" or "troy weight," which is mostly used for gold, gems, and medicines.

Most countries just use the metric system, where 1,000 milligrams make a gram and 1,000 grams make a kilogram. They don't fret about how many stone a person weighs.

Is there any way to switch to sanity? Yes! All the world has made the switch. In almost every nation, schoolchildren can learn all they have to know about measurement in one day. And they can remember it for the rest of their lives.

Switching now would be difficult for a while. Would it be worth it? That's a tough question; to help answer it, consider another question, one we talked about before: How many inches are there in a mile?

Don't remember how to work it out? Maybe that gives you your answer.

Art by John Huehnergarth

Adapted from a 1971 Saturday Evening Post article & used by permission.
COPYRIGHT 2005 Benjamin Franklin Literary & Medical Society, Inc.
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Author: Printer friendly Cite/link Email Feedback Asimov, Isaac Jack & Jill 1USA Nov 1, 2005 492 Jack and Jill puzzler. Christmas-wreath bread. Metric system