SI  metric system
The SI System
 SI is the modernized version of the metric measurement system. (Système International d'Unités)
 The metric system is based on seven base units.
 SI measurements are expressed with decimals, not fractions (1.5 , not 1 ½)
 Other measures of length are based upon multiplying or dividing the meter by 10.
 A prefix is added to the word 'meter' to describe these other measures.
The Meter
 The meter is the unit of length used in the SI measurement system.
 In 1793, the meter was defined as 1/10,000,000 of the distance from the pole to the equator.
 Over the years, standard meter length bars of brass, platinum, and platinumiridium were used.
 In 1983, the length traveled by light in vacuum during 1/299,792,458 of a second was defined as one meter.
SI Prefixes

mega (M_): 1,000,000 of the base units (10^{6}).Example 1,000,000 meters = 1 Mm

kilo (k_): 1,000 of the base units (10^{3}).Example 1000 meters = 1 km

centi (c_): 1/100 of the base units (10^{2}).Example .01 meters = 1 cm

milli (m_): 1/1000 of the base units (10^{3}).Example .001 meters = 1 mm

micro (µ_):1/1,000,000 of the base units (10^{6}) .Example .000001 meters = 1 µm

nano (n_): 1/1,000,000,000 of the base units (10^{9}) .Example .000000001 meters = 1 nm

pico (p_): 1/1,000,000,000,000 of the base units (10^{12}).Example .000000000001 meters = 1 pm
Equivalent Measures
 1 meter = 100 centimeters = 1000 millimeters
 1 m = 100 cm = 1000 mm
 1 cm = 10 mm
Questions
Using a meter stick, answer these questions:
 My hand span is ________ centimeters. (Measure outstretched hand between tip of thumb and tip of little finger)
 The width of my _____________ fingernail is 1 cm. (Find the fingernail that is the closest)
 The width of the back my hand is _________ cm. My height is _____________ m.
 The width of my table is ___________ m.
 The table length is ___________ m.
Prefix  Symbol  10^{n}  Decimal  Short scale 

exa  E  10^{18}  1000000000000000000  Quintillion 
peta  P  10^{15}  1000000000000000  Quadrillion 
tera  T  10^{12}  1000000000000  Trillion 
giga  G  10^{9}  1000000000  Billion 
mega  M  10^{6}  1000000  Million 
kilo  k  10^{3}  1000  Thousand 
10^{0}  1  One  
centi  c  10^{2}  0.01  Hundredth 
milli  m  10^{3}  0.001  Thousandth 
micro  µ  10^{6}  0.000001  Millionth 
nano  n  10^{9}  0.000000001  Billionth 
pico  p  10^{12}  0.000000000001  Trillionth 