Today marked the beginning of my annual drive to convince students that the common system of measurement currently used in the United States of America is ridiculous. The conversion tables from one unit to the next are enough to drive someone crazy. Add to that the fact that most of the measurements were purely arbitrary in the first place and we get a general sense of a measurement system that, while usable, is just plain silly.
Compare that to the International System of Measurements, also known as SI (system internationale) or, more commonly, the metric system: the units are based on rational measures, there is an ease of conversion that requires simple knowledge of the multiples of ten, and there is a beautiful relation among the units for length, mass, and volume. (Those who revel in technicalities will probably inform me that the base units do not actually include volume, but do include time, temperature, luminosity, current, and quantity. To those I simple respond that I am teaching fourth graders and there is wisdom in keeping things simple.)
So today we began learning about the metric system. We started with units of length. I showed the students a meter stick and asked them to tell me what it was and how it was used. Then we discussed decimeters, centimeters, and millimeters and the kinds of objects that would be most reasonably measured using those units. A couple of students pointed out that there are even smaller units, such as the nanometer (a unit of length equal to 0.000000001 m) and even the femtometer (0.000000000000001 m). After going through the most common small units, we looked at the larger units, such as the decameter (10 meters) and the kilometer (1,000 meters). Several students wanted to know what the unit for 100 meters is called. Rather than telling them, I decided to let the students work it out. After searching their math glossaries, our dictionaries, and sharing a few guesses, someone finally noticed that there was a lovely chart in their math binders that gave them the answer (hectometer).
It was a fun way to introduce the metric system. We will spend the rest of this week and the next to explore the rest of the more common base units of metric. While I don’t know if any of my students will ever be in a position to get our nation to finally drop the customary system of measurement, but that won’t stop me from advocating for it every year for the rest of my life until it finally happens!