Learning the metric system of measurement is a piece of cake with the right tools. The English system has an incredible array of conversion factors, and no two are alike. The metric system, on the other hand, uses a standard set of prefixes to indicate relationships between units. This simplifies matters immensely.
Metric System Basics
The metric system is based on standard units for different kinds of measurement. Common units are the meter (for linear measure), the liter (volume), and the gram (weight). Standard prefixes indicate the multiple or fraction of the base unit in terms of powers of 10.
Metric System and the Decimal System
It is important to understand that the metric system is based on the same decimal system that allows us to use place value with numbers. Metric measurements use the same digits, no matter what size of units are the focus. For example, an item that measures five (5) meters also measures five hundred (500) centimeters and five thousandths (.005) of a kilometer. The digit "5" does not change. The change involves the decimal point and is accomplished by multiplying or dividing the measurement by the correct factor of 10. This makes conversion between units of various sizes simply a matter of moving the decimal point the correct number of places in the correct direction.
Metric System Prefixes
The heart of the metric system is the system of prefixes that indicate the relative size of the fractions and multiples of the base units. The same prefixes are used for all of the metric measurements, whether for length, volume, or weight. They have the same relationship no matter which base unit is being used.
The prefixes in common usage to indicate fractional parts of the base units include deci-, centi-, and milli-. Deci- indicates that the base unit is divided into ten pieces (1/10ths) or moving the decimal point one place to the left. The centi- prefix indicates division into hundredths (two places to the left), and the milli- prefix indicates division into thousandths (three places to the left). In science, the prefix micro- indicates a millionth and nano- indicates a billionth.
Other prefixes indicate larger measurements than the base unit. Deca- indicates the base unit is multiplied by a factor of ten (moving the decimal point one place to the right). Hecto- indicates a multiplier of one hundred (two places to the right), and kilo- indicates a multiplier of one thousand (three places to the right). Other prefixes, such as mega- and tera- indicate even larger multipliers commonly used in scientific fields.
Learn to Use the Metric System
A handy tutorial for multiplying and dividing by 10s can be found at the Open University at openlearn.open.ac.uk/mod/resource/view.php?id=289639.
The prefixes must be memorized in order of their relative sizes. One way to do this, according to R.S. Schaeffer, math teacher at Kutztown University in Pennsylvania, is through the use of mnemonics. He recommends putting the units in order of size and creating a sentence with words beginning with the same letters, such as "King Henry Died by Drinking Chocolate Milk" which stands for kilo-, hecto-, deca-, base, deci-, centi-, and milli-.
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