METRIC
SYSTEM
&
SIGNIFICANT
FIGURES
Metric Units, Dimensional Analysis, and Significant
Figures
United States, Liberia, Myanmar
The Metric System
Scientists use the International System of Units, or “SI
System” (also called the metric system)
!  SI base units are used for consistency among
scientists, who may be from different countries
! 
Measurement
Length
Mass
Volume
Time
Temperature
Base Unit
meter (m)
gram (g)
Liter (L)
second (s)
Kelvin K
Prefixes
! 
The SI System is a decimal system based on 10
Prefix
kilo-
(k)
Thousand 1,000
hecto- (h)
Hundred 100
deca- (da)
Ten 10
BASE
One 1
deci-
(d)
Tenth (.10)
centi-
(c)
Hundredth (.01)
milli! 
Meaning
(m)
Thousandth (.001)
“King Henry Died By Drinking Chocolate Milk”
Metric Conversions
! 
There are 2 ways to convert between units:
1. 
2. 
! 
! 
Move the decimal
Dimensional Analysis
Moving the decimal works with the metric system
because it is based on 10, BUT…
IF you are asked to convert between time units, or
other units not based on 10, you have to use
dimensional analysis (especially in CHEMISTRY and
PHYSICS)
Example Problems
! 
Convert 1750 mm into dm
! 
Convert 4 hL into L
! 
Convert 3 years into minutes
! 
Convert 68 cg into dag ( use D.A.!)
For the Record Activity