Today's soundtrack is Holy Soldier: Last Train.
I'm now on chapter 15 of Basic Math & Pre-Algebra for Dummies, "How Much Have You Got? Weights and Measures". This chapter title bothers me; shouldn't it be "How Much Do You Have"?
The chapter begins by introducing the concept of units of measurement, which allow us "to count something that isn't discrete: an amount of a liquid or solid, the distance from one place to another, a length of time, the speed at which you're traveling, or the temperature in the air" (p. 205). The two most-used systems of measurement are English and metric.
The book here covers common units of measurement of the English system of measurement, used primarily in the United States, then goes on to identify the five basic metric units: metres for distance, litres for volume (capacity), grams for mass (weight), seconds for time, and degrees Celcius for temperature. The metric system builds units "using a basic unit and a set of prefixes" (p. 208). There are ten metric prefixes that we use to identify how many of something we are looking at (for example, a kilometre is 1,000 metres): giga- for one billion, mega- for one million, kilo- for one thousand, hecta- for one hundred, deca- for ten, no prefix for a single unit, deci- for one tenth, centi- for one hundredth, milli- for one thousandth, micro- for one millionth, and nano- for one billionth.
Some quick-and-easy estimates for converting between English and metric measurements: a metre is approximately a yard; a kilometre is approximately half a mile; a litre is approximately 1/4 gallon; a kilogram is approximately two pounds; and for temperature...32f is 0c (cold), 50f is 10c (cool), 68f is 20c (warm), 86f is 30c (hot). Some more specific conversions are as follows: 1 meter ~ 3.28 feet; 1 kilometer ~ 0.62 mile; 1 liter ~ 0.264 gallon; 1 kilogram ~ 2.2 pounds.
The book went over something about using conversion factors to convert units, which didn't click for me. Here's the method that I use:
To convert from metric units to English, just multiply the number of units that you want to convert by the other side - for example, 7 metres times 3.28 feet = 25.34 feet. To convert from English units to metric, divide the number of English units by the value that the English units are compared to their metric counterpart - for example, 7 feet divided by 3.28 is 2.13 metres.
