Five Reasons why the Metric System is Easier to Use than the Imperial System of Weights and Measures

This page is still a work in progress. Although it is not complete, I decided that there was enough helpful information here to justify uploading it before I was entirely finished with it (whenever that day will come).

Even though most Americans have heard of the metric system, and are somewhat familiar with it (we use it when we buy those two-liter bottles of soda, and most of the time when we buy medicine or vitamins, or compare the sizes of automobile engines--my Toyota Sienna's manual says that the engine is 3.2 liters), we are hesitant to use it. There are probably a few reasons for this. The major one most probably, is that it seems so awkward when converting from inches and feet to meters, or from cubic inches and feet to liters. Most Americans are introduced to the metric system merely by being told that you multiply centimeters by 2.54 to get the equivalent number of inches. This is one reason why many of us cringe when we hear of the metric system. Why should we have to go through all these conversion problems? The bottom line is that any new system of weights and measures would be considered awkward, if the only experience you have of it is simply converting a familiar system to that newer one. The way to learn the metric system is not to think "OK, how many inches or gallons is this?" but simply to use common, everyday comparisons.

There are five reasons why the metric system is easier to use than the imperial system. The metric system is:

1. Ten-based

Each smaller and larger unit in the metric system is multiplied by a factor of 10. For example, a kilometer is simply 1,000 meters, so 5,000 meters is 5 kilometers. A centimeter is 1/100 of a meter, so 5,000 meters would be 500,000 centimeters. A milllimeter is 1/1,000 of a meter, making 5,000 meters, 5,000,000 millimeters. Moving from one unit to the other is much much easier than multiplying the number of feet by 12, to get inches, or the number of miles by 5,280, to get feet. In the same way, a kilogram is 1,000 times the weight of a gram, and a kiloliter (also a cubic meter) is 1,000 times larger than a liter.

In fact, working with the metric system is so easy, you really don't have to (mentally) multiply or divide. You can easily convert from millimeters to meters, bysimply  moving the decimal. For example, 572 millimeters is .572 meters. And 4,026 meters is 4.026 kilometers.

If you don't think that such conversions are a big deal, think for a second about our own currency, which has been decimalized since 1792, when Congress, at Secretary of State (and future President) Thomas Jefferson's recommendation, enacted that our dollar be divided into a hundred cents. We know without even thinking about it, how to convert from pennies to dollars. How many dollars are 2012 pennies?  $20.12. You don't have to do math; you just move the decimal. Now try to convert 2012 inches to feet. See how much easier a decimalized sysetm is?

2. Self-explanatory

The terms of the metric system themselves, provide the definitions of the terms. For example, the Latin prefixes "milli-" and "centi-" mean one thousand and one hundred, respectively, and so the millimeter is one-thouasandth of a meter, while the centimeter is one-hundredth of a meter. Similarly, the prefix "kilo-" comes from a Greek root khillios, meaning "thousand."  And so any time you see the prefix "kilo-", you know that it means a thousand of the basic unit (meter, gram, or liter). There is no more wondering how many grains are in an ounce or a pound; how many gallons are in a bushel or barrel, etc.

When using the metric system, you no longer have to wonder what a peck or bushel or hogshead is. The terms are self-explanatory. There are always the base units (-meter, -gram, or –liter), and then the prefix. The two things to know about metric prefixes are that they are simply terms that represent numbers (specifically, powers of ten), and that they are the same across meters, grams, and liters. To use some of the more common ones, kilo means “thousand,” and so a kilogram is 1000 grams; a kilometer is 1000 meters; milli means “one-thousandth,” and so a milligram is 1/1000 of a gram; a millimeter is 1/1,000 of a meter; a milliliter is 1/1000 of a liter.

3. Standardized

Every meter is the same length; every liter has the same volume; every kilogram has the same weight. There is no more wondering how much a troy ounce is, compared to the avordupois; or comparing British gallons or pints to their American counterparts, or wondering how many pounds are in a long ton, or a short ton.  There is only one meter, one kilogram, one liter.

4. International

It is the legal system of weights and measures of every country (with the exception of a few, including America). Now this doesn't mean that whatever the rest of the world does, should immediately be copied by the United States. But using the same system of measurement as the rest of the world will mean that nobody every has to do any conversions, from one system to another.

5. Inter-related

As one might imagine from its name, everything in the metric system is based on the meter. If you know the meter and a few prefixes, you know the metric system. Units of length are based on the meter itself;; units of area are similarly based on the square meter. The base unit for volume or capacity is the liter, which is a cubic decimeter (a decimeter is one-tenth of a meter). Another way of looking at the liter, is that it is a thousand cubic centimers (or a thousand milliliters). Weight is also based on the meter as well. The kilogram is the weight of a liter of water. A gram is the weight of a cubic centimeter of water (also known as a millilieter).

One can see how with the metric system, one can quickly go from using meters to measure length, to determining the volume of a certain amount of material; if it is water, one can then quickly enough determine how much it weighs as well.

A liter is the amount of water in a one-liter bottle, and half of the liquid in those two-liter bottles of soda. More mathematically, a liter is the amount of space of a cube that is a tenth of a meter on all its edges.

Remember our one-liter bottle of water? A kilogram is the weight of that much water. If you want to use smaller units, a gram is the weight of a cubic centimeter (which is the same as a milliliter) of water, or a paper clip. An American nickel is 5 grams.

A few questions about the metric system:

1. Don't they keep changing the definition of the meter?
Yes, but this is actually a reason to use the system, not a reason to reject it. Originally, the meter was defined as 1/10,000,000 of the distance along one of the lines of longitude that passed through Paris, France (one-ten millionth, that is, of the meridian's span from the North Pole to the Equator).  They were pretty darn close, given that they were working in the 1790s. And so in 1799, a platinum bar, known as the Meter of the Archives, was created, which would serve as the international standard for the meter. This served as the standard for much of the 1800s.  In 1889, a new standard was created, a bar made of platinum-iridium. However, simply retaining a stick of metal in Paris, and hoping that this metal rod won't bend, or otherwise change its length, is not sufficient when you are conducting scientific experiments in the atomic age, and require incredibly precise measurements. Nor is it acceptable, to simply make copies of this metal bar, and then send them out throughout the entire world (for other countries to use as their standard), hoping that all of these bars will retain the exact same length. Therefore, more modern definitions of the meter were adopted. In 1927, the International Bureau of Weights and Measures (the international body dealing with these standards) defined the meter as 1,553,164.13 times the wavelength of the red spectral line emitting from cadmium (at a given air pressure and temperature), which was found to be very regular.And to further increase the accruacy of the metric system, in 1960, the meter was defined as 1,650,763.73 wavelenths of the orange-red radiation of krypton 86. And in 1983, the definition of the meter was changed yet again. It was defined as the length of the path traveled by light in vacuum during a time interval of 1/299,792,458 of a second (now you might be wondering how we are to measure a second, but this has already been taken care of, with atomic clocks that measure time with an uncertainty of one second in 3,168,876 years).

Such precision is not a reason to reject the metric system, but to adopt it. It would be very difficult to use a supposedly international system of measurement, if in fact every nation's prototype was slightly different from every other nation.

2. Why can't we simply let whoever wants to use metric, use it, while whoever wants to use the imperial units, use them?
Have two separate systems of measurement is insanity, and a recipe for disaster. Yes, it is that serious. And because some of our companies work in metric, and others don't, there is always the possibility of mixups because one company is assuming that certain numbers are metric (or customary). Don't think that this could ever become a problem? Think again. In 1999, NASA lost a $125 million Mars Rover, because Lockheed Martin, one of the sub-contractors, calculated units with the cutomary units, while NASA was using metric. The spacecraft came in about 100 kilometers closer than planned, some 25 kilometers beneath the lowest level that it could safely function.

3. Isn't the imperial system more American? Isn't the metric system anti-American?
Very often in the discussions about this system, one sees metric proponents making insulting remarks about America--essentially how stupid, stubborn, or arrogant we are, to resist using a system of measurement used by pretty much the rest of the planet. There are few things in life more frustrating that seeing a great idea, poorly argued for. Making patronizing or insulting comments to people about their position isn't a very good way of convincing them to change to yours. Let's ignore the communication problems here, and just look at the Americans who have argued for the metric system in the past.

George Washington in his State of the Union addresses to Congress, three times urged it to adopt a system of weights and measures that was __________. James Madison, again urged Congress to adopt this system. John Quincy Adams, son of the second President John Adams, and himself the sixth President of our country, submitted a massive report to Congress while Secretary of State in 18__, and admitted that the current implementation of teh metric system was flawed, but said that ________________. Alexander Graham Bell, the famous inventer, testified to Congress in 1906, encouraging it to make the metric system the official system of measurement in our country. 

Interesting metric links:

Alexander Graham Bells' testimony to Congress in 1906. He explained how easy the metric system is to learn and to use (not only for his research assistants, but also for his mechanics). He stated that he started using the metric system himself, because he was making complex calculations trying to build kites that could lift a man into the air, and it was too difficult in the customary measurements. He realized, however, that after performing his calculations in metric, that trying to convert them to the customary units (so he could get models built by people working with customary measurements) opened up the likelihood that a mistake would be made (in converting the units from one system to the other), so he decided to transition his entire laboratory to metric. His testimony begins on page 262 of that book (which is available on Google Books for a free download).

The report issued by Congress in 1866

The report issued by John Quincy Adams in 1821 to Congress. This report isn't something that I'd recommend anyone trying to read if they only have 30 minutes of time to devote to this top, but it is the full report (starting on page 55; the book itself is available as a free download) that he issued. This is a massive study not only into the metric system itself (which he wasn't entirely sold on, although some improvements that he wanted to see in it have been made), but also, the history and development of a variety of traditional units of measurement, with special attention paid to those in England, as our American units had evolved from the English units.

Google's Online Metric-Customary Converter

In your browser, type in a number and the unit of measurement, and then add, "in miles," or "in km," and hit Enter. Google will give you the number in the unit you want it converted to. It works with units of length, volume, and area. See, for example, the request to convert 10 miles into kilometers. Do keep in mind that if you type in the letter m, Google will think you mean meters. If you mean miles, you can use the abbreviation mi.

The booklet Weights and Measures Standards of the United States: a Brief History (produced by the US National Bureau of Standards, part of the US Department of Commerce) provides an excellent look at the various definitions of both metric and imperial units.