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The Metric System







There are four basic metric measurement units:


          • Length = meter (m)                        


          • Volume = liter (l)                           


          • Mass (weight) = gram (g)                 


          • Temperature = ° Celsius (° C)       



All four metric system basic units can be converted into larger or smaller units simply by adding a prefix in front of the basic unit:



          Unit prefixes:


  • kilo (k) = Makes the basic unit 1000 times larger (103)
  • deci (d) = Makes the basic unit 10 time smaller (10-1 or 1/10)
  • centi (c) = Makes the basic unit 100 times smaller (10-2 or 1/100)
  • milli (m) = Makes the basic unit 1000 times smaller (10-3 or 1/1000)
  • micro (µ) = Makes the basic unit a million times smaller (10-6 or 1/1,000,000) 


For example, a person might weigh 63,000 grams. That same person also weighs 63 kilograms (kg) since each kilogram is equal to 1000 grams.

These larger and smaller units are called “derived” units




A) Length


The basic unit of length in the metric system is the meter (m). Common derived units are the centimeter (cm) (10-2 or 1/100 of a meter) and the millimeter (mm) (10-3 or 1/1000 of a meter). For measuring large distances, the kilometer (103 or 1000 meters) is often used.



B) Volume


The basic unit of volume in the metric system is the liter (l). The most common derived unit is the milliliter (ml) (10-3 or 1/1000 of a liter). The volume of a milliliter is equal to the volume of a cube 1 centimeter per side.

(The ml is often called the cubic centimeter (cc) in the medical field).

Another derived unit is the micrometer (µl) (10-6 or 1/1,000,000 of a liter).



C) Mass (weight)


The basic unit of mass in the metric system is the gram (g). The most common derived unit is the milligram (mg) (10-3 or 1/1000 of a gram). For measuring large masses, the kilogram (103 or 1000 grams) is often used.



D) Temperature


The basic unit of temperature in the metric system is the degree Celsius.

(° C ). There are no commonly derived units.


To get a feel for degrees Celsius, consider the following temperatures:


          • Ice water and the freezing point of water are 0 ° C


          • Room temperature and tap water are 20 – 25 ° C


          • Normal body temperature is 37 ° C


          • Water gets too painful to touch between 50 – 60 ° C


          • Water boils at 100 ° C