## 2010-10-15

### Mass makes the world go 'round

Some people might consider metrication a massive undertaking, but it can actually be very easy to accomplish if people put their weight behind the effort. Let's address that effort literally....

The unit used to measure mass in the International System of Units (SI) is the kilogram. (Yes, you read that correct; the base unit is the kilogram, not the gram.) I find beauty in the use of kilograms by way of its (approximate) relation to volume, but that's another topic.

Before getting to my key conversion points for mass, I want to point out that SI is already in wide-spread use for mass (and volume) for drug prescription/purchase/use (both legal and illegal). So, for many, the conceptualization of mass (whether it's a milligram or a kilogram) has already been well established.

Mass Key Conversion Points (kilogram / pounds):
0.5 kg ≈ 1.1 lbs
* 1 kg ≈ 2.2 lbs
** 5 kg ≈ 11 lbs
10 kg ≈ 22 lbs
25 kg ≈ 55 lbs
50 kg ≈ 110 lbs
* 100 kg ≈ 220 lbs
If you can remember the 1 kg = 2.2 lbs rule, then you should have an easy time performing the rough multiplication to convert. For example, 11 kg = 10 kg + 1 kg = (2.2 lbs * 10) + 2.2 lbs = 22 lbs + 2.2 lbs = 24.2 lbs.
It may be even easier to rely on the 5 to 11 rule; as five is a very easy number to round to and 11 multiplies easily enough1. For example, 500 kg = 5 kg * 100 = 11 lbs * 100 = (10 lbs * 100) + (1 lb * 100) = 1000 lbs + 100 lbs = 1100 lbs.

As far as reversing the conversion, just remember that 2 lbs is "a little less" than 1 kg and then you can adjust the conversion once you have an estimated kilogram value. For example, 300 lbs "is a little less than" 150 kg... 150 kg = 5 kg * 30 = 11 lbs * 30 = (10 lbs * 30) + (1 lb * 30) = 300 lbs + 30 lbs = 330 lbs.

1 For you math whizzes: Yes, the multiplication of 11 can be made into one step, but I tried to make it easy to digest for the general populace by breaking it out into 10 and 1.

AUTHOR'S NOTE: I apologize for the three day delay in posting; I've had some difficulty accessing the internet during times which are appropriate for blogging. I plan to write and date the "missed" entries (this one included) as if they were written on time, for organizational purposes.