Which country does not belong in the following list: Burma, Liberia, Somalia, United States?

(Time to think)

OK, that was not too difficult. Somalia has made the step to metric (SI) units already half a century ago, and therefore does not belong in one list together with the three remaining countries that haven’t embraced the metric system yet.

One of the first things most Europeans (and people from other parts of the world as well) struggle with once they come to the United States is the fact that nothing is measured the way they are used to. The metric system – an (almost) universally accepted standard to measure length, area, volume, mass, etc. – is so ingrained in almost everybody’s brains (i.e. everybody outside of the U.S.) that not being able to use it as a set of reference units in daily life throws people for a loop.

Even the thermometer (note: it’s called thermo*meter* not thermo*perial*) in our car is still set on Celsius, even though that seems to be one of the easier units to convert in your head. For example, when trying to make sense of Fahrenheit temperatures I use this formula: Substract 32 from the °F total, devide the rest by 2 and then round it up a little. This isn’t accurate, because the actual formula is [°C] = ([°F] − 32) × 5⁄9. I don’t know about you, but I have a hard time dividing by 1.8 in my head. So this rule of thumb has served me well.

It goes without saying that metric SI units outperform non-metric units such as the Burmese and the US units in terms of reduced ambiguity and ease of use. Anyone capable of shifting decimal points can work with metric units. Working with non-metric systems is a much more elaborate undertaking.

Let’s take a simple example. How large a cube do you need to build for it to contain 1 liter? That’s easy. One liter is a decimeter cubed, so a cube with sides of 1 decimeter (0.1 m) a side will do.

Now the same problem in US customary units. How large a cube should you build for it to contain a gallon?

Ehhm, that depends: do you mean a liquid gallon or a dry gallon?

Hmmm, don’t see why that should matter, but let’s say the cube is to contain water. I guess that should make it liquid gallons?

Right, liquid gallons it is. Let’s see, if I remember correctly, 77 cubic feet equals 576 liquid gallons. So that would make one gallon equal to 77/576 cu ft. To get such a volume you need a cube with edges in feet that are equal to the third root of 77/576 which is… ehhh… got a pocket calculator?

Metric opponents often object that Burmese and US units, being based on the old British imperial system of units, are more convenient when it comes to calculations that involve division by three. This is a nice example of the tail wagging the dog. Clearly, as the world has (almost) unanimously opted for base ten rather than base six (or twelve), the ease of division by three is not all too important.

**The Metric System SI**:

- It is based on a decimal system (ie. powers of ten). Therefore, it simplifies calculations by using a set of prefixes
- “milli” means 10^-3 or 0.001
- “centi” means 10^-2
- “deci” means 10^-1
- “deca” means 10^1
- “hecto” means 10^2
- “kilo” means 10^3 or 1000

- It is used by most other nations of the world, and therefore, it has commercial and trade advantage

**The Imperial System**:

- Used in majority by the US
- Much more complicated than the Metric System
- The units come from body parts
- Twelve inches = one foot
- Three feet = one yard
- Five and a half yards = one rod, pole or perch
- Four poles = one chain
- ten chains = one furlong
- Eight furlongs = one mile or 5280 feet

- Inches are divided using many “bases” 1/2 1/4 1/8 1/16 1/32

Now, if you want to hear more about it, take a look at this: