## Monday, June 06, 2005

### Give them a Centimeter and they'll take 2.54

I am a member of a computer user group and this post originally appeared there.

One of the members was complaining about computer monitors still using DIP or "dots per inch" and the metric ruler on the word processor using 1/2, 1/4 and 1/8 measurements.

Just to play the devil's advocate here a minute.

Libraries, and book binders do divide up centimeters into 1/8's so that is the reason for centimeters appearing in eights on your word processor. 1/2, 1/4, 1/8 are easier terms for most people to work with and make more sense than pure decimals unless you need a great deal of precision.

BTW I live in China so don't confuse me with an American. I am however, a committed Francophobe and would hate the metric system simply because it comes from evil, decadent, France. However, there are other reasons not to like it as well.

Most of this information comes from an article in a science magazine (Discover, Scientific American, or something like that) several years ago that talked about the metric system and how unscientific and unrealistic the metric system is. Other parts of it are my own observations

Some examples of problems with the metric system:

The most common recommendation of the metric system boils down to statements like "It is easier to use a decimal system and that it is a finer scale. (The second of these does not apply to centigrade). That is true but over played. If you get past the 12 inches in a foot rather than 10 based system there is no significant difference in the ease of use. The 12 comes from ancient Rome so blame the Romans. In some ways the metric system is harder to use because the measurement units are confusing because they are in a dead language. People must learn that it goes millimeter, centimeter, meter, kilometer, decameter. All the words end in "meter" and many people don't know why a millimeter is one 1000th of a meter and not 1000 meters. The reason is actually Latin grammar. Thus the names of units in the metric system are only more logical if know Latin. Otherwise they are, just like the old English (Inches predate the Empire so the term Imperial is incorrect)arbitrary names and both are confusing because of Latin (12 inches in a foot and Mili, centa, Etc.)

What is a meter? How do you find one?

A meter Has at times been defined as:
1. A percentage of the distance between two French cites.
2. The length of a certain bar of platinum in a vault in France
3. Currently, A meter is defined as a single wavelength of orange light emitted by some element charged to a certain polarity in a vacuum at zero degrees centigrade or some such. Yeah, real common and easily to get measurement.
If you lost a meter stick and if you go through all the definitions of a meter you might be really tempted to conclude that the best definition of a meter is still 39.25 inches. The fact is that a meter is an arbitrary number just like a foot or yard. But unlike a foot or yard it is not an arbitrary number based upon any easily observable distance.

By contrast a mile 1/24000 of the Earth's diameter at the equator. Thus a mile works out to a 6 second delay in sunrise time at the equator and could in theory be figured with two cheap digital watches.

An inch is about the distance from the middle of the first joint to the end of a man's thumb. This is, contrary to what you may have learned in university, the origin of the term "Rule of thumb."

A foot is still about the average length of a average man's foot in a pair of pointed toed boots.

A meter is also too long for many measurements and the sub units do not conform to any easy to reproducible distance.

As a meter is too long a liter is too small.

A gallon is actually based upon the size of a bucket. Buckets developed under trial and error (scientific method) and a gallon bucket is the largest size that can be comfortable carried in one hand. There is no equivalent measure in the metric system.

A teaspoon is a small bite table spoon is a large bite

An ounce is fluid mouthful cup is eight such mouthfulls Pints, quarts and gallons all fit together in that they represent normal units used by normal people.

In the end the only real reason to use the metric system is a finer scale. It isn't any more scientific or logical than any other system. The names are not easier to learn and it does not conform to the real world but imposes itself upon the world.

Don't even get me started about horse Power versus Newtons.

So in the end the only real advantage of the metric system is that it is based on 10's and is thus easier to move between units. In other words, it works better on a calculator. That is fine and good if you are doing calculus. Otherwise it is simply a pain.