The Metric System Catherine Le (Ilona Davies) The Harker School

2 Brief History of Measurement

3 The Metric System

4 SI Units of Measurement: Metric System Scientists all over the world use a set of measuring units called the International System of Units (SI). SI is a revised version of the metric system, which is based on multiples of 10. SI is built upon seven base units and many derived units. For example, the base unit for length is meter (m) and the derived unit for volume (length x length x length) is cubic meters (m 3 ).

5 SI Base Units (Video Review) Length Meter (m) Volume Liter (L or l) Mass Gram (g)

6 SI Base Units Reference:

7 Examples of SI Derived Units QuantityUnitSymbol Areasquare meterm2m2 Volumecubic meterm3m3 Speedmeters per secondm/s Accelerationmeters per second squaredm/s 2 ForcenewtonN = kg.m/s 2 EnergyjouleJ = kg.m 2 /s 2 PressurepascalPa = kg/m.s 2 DensityGrams per cubic centimeterg/cm 3

8 Metric System of Measurement Measurements must have a value and a unit (for example, 53 meters). A metric prefix indicates how many times a unit should be multiplied or divided by 10. For example, 1000 meters = 1 kilometer. The prefix “kilo-” tells us that we need to multiply km by 1000 to convert to m. A conversion factor is a ratio of equivalent measurements that is used to convert a quantity of one unit to another. To convert s to ms, you would multiply by a conversion factor of 1000 ms/1 s.

9 Some SI Prefixes PrefixFactorPrefixExample mega-10 6 MMegameter ( meters) kilo-10 3 kKilometer (1000 meters) hecto-10 2 hHectometer (100 meters) deka-10 1 daDecameter (10 meters) 10 0 Meter (1 meter) deci dDecimeter (0.1 meters) centi cCentimeter (0.01 meters) milli mMillimeter (0.001 meters) micro µMicrometer ( meters)

10 Metric Conversions

11 Metric Conversions

12 Metric Stairs Decimal Moves Right one place for each step you go down. Kilo Hecto Deca Base Unit (Meter Liter Gram) Deci Centi Milli Decimal Moves Left one place for each step you go up. UP RULE DOWN RULE

13 Checkpoint! What is the numerical value of the following prefixes? Deci = ________________ Hecto = ________________ Milli = ______________ Deca = ________________ Kilo = ___________________ What is the unit of measurement for the following? Length = _________________ Volume = _________________ Mass = ________________

14 Checkpoint! 1 km = ____________ m 1 m = ____________ cm 1 mm = ____________dm 1 dm = ____________ dam 1 liter = ____________ cm 3 (Hint: 1mL = 1 cm 3 ) 1 kg = ____________ g