thinkMetric®
Lesson 1 - Height
Our first point of reference is a door, just a regular plain old door in anybody’s residence. Almost all of them are approximately 2 meters in height. So if you fit through the door with a little space to spare, you are probably a little less than 2 meters in height. That’s what you have in common with 99.9% of the population. What’s your height exactly?
In a great act of emancipation from the British system of measurement, the Mendenhall Order of 1893 stipulated that henceforth all U.S. customary units of measurement would be defined in terms of metric units. The master foot in London became irrelevant. Perhaps you can look at the Mendenhall Order as equivalent of the Boston Tea Party what metrology is concerned. The definitions were slightly changed in 1959. Since then, the conversion from inch to centimeters is 1 inch = 2.54 centimeters exactly, a good number to remember.
So now you know your height. Let’s say it is 177 centimeters. How do you tell somebody how tall you are? Basically, you talk about meters and centimeters the same way as you talk about dollars and cents. Let’s say you walk into a 7-eleven and you see something you want to buy. It doesn’t have a price on it, you ask the clerk and he responds: “It’s one seventy seven.” Is he talking about dollars or cents? It’s not clear. If he said it was one hundred and seventy seven, it would be clear he meant cents. If he said it was one point seventy seven, it would be clear he meant dollars. With “one seventy seven” we can’t tell, and it doesn’t matter, the price is the same.
Since you already talk and think like the sales clerk in the 7-eleven, you can call yourself a decimal native, that means you unconsciously know how to switch back and forth between different units of measurement (dollars and cents). It is not a big step to go from here to become a metric native. All you need to do is learn a few points of reference, like the average height of a residential door being 2 meters, and, of course, your own height.
So how do you tell your height? “I am one seventy seven.” Are you talking about meters or centimeters? It doesn’t matter. The height is the same.
By the way, don’t worry about anybody thinking you are giving your weight when saying: “I am one seventy seven.” With weight, you specify kilograms, like “ I am 71 kilos”
|
One dollar |
One meter |
|
= 10 deci-dollars (dimes) |
= 10 deci-meters (dm) |
|
= 100 centi-dollars (cents) |
= 100 centi-meters (cm) |
|
= 1000 milli-dollars (mills) |
= 1000 milli-meters (mm) |
One of the ways a mill is used.
A Point of Reference to Remember
|
Typical residential door height |
2 m |
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