THE METRIC SYSTEM
September 9, 2012
WHY DO WE USE THE METRIC
SYSTEM?
Almost all other countries are using the
metric system
 Other countries’ companies are refusing to
buy products from the U.S. if not labeled in
metric units
 Scientists need a universal way to
communicate data (SI Units)

MATH AND MEASURING



Math- the language of Science
SI Units – International System

MKS
 Meter (m)
 Mass (kg)
 Time (s)
Prefixes plus base units make up metric system
 Example:
 centi + meter = centimeter
 Kilo + liter = Kiloliter
THE METRIC SYSTEM MEASURES:
Basic
Measurement
Definition
Unit
Abbrevi- Instrument Used to
ation
Measure
Length
Distance between two meter
points
m
Mass
Amount of matter in an grams
object
g
Time
Interval between two second
occurrences
s
Meter stick,
centimeter
ruler
Balance,
electronic or
triple beam
Clock,
stopwatch
Temperature
A measure of heat
intensity
Celsius
Kelvin
°C
K
Celsius
thermometer
Amount of a
Substance
The number of basic particles
of a substance in a gram
molecular mass of that
substance 6.02 *10 23 particles
mole
M (mol)
Balance
THE METRIC SYSTEM MEASURES:
Derived
Measurement
Definition
Unit
Volume
Amount of space an
object occupies
liter
Density
Mass per unit volume Grams/
Liter
Abbrevi- Instrument Used to
ation
Measure
L
Graduated
cylinder
g/L
g/cm3
Balance,
electronic or
triple beam
Metric System Prefixes


These prefixes are based on powers of 10
What does this mean?

From each prefix every “step” is either:

10 times larger
or


10 times smaller
For example

Centimeters are 10 times larger than ___________
1 centimeter = _____ millimeters
Name
Symbol
Numerical
Value
Power of
Ten
megakilohectodecaBasic
Units
M
k
h
da
meters,
liters,
1,000,000
1,000
100
10
grams,
seconds
106
103
102
101
100
deci
centimillimicro-
d
c
m
µ
0.1
0.01
0.001
0.000001
10-1
10-2
10-3
10-6
Metric System Conversions

To go from a LARGER to a smaller prefix, move the
decimal point to the right
 First write prefixes as powers of ten
 Find the differences in powers of ten
 Move the decimal point as many places to the right
as the difference in powers of ten
Example:
1.6 liter = _1600__ milliliters
Metric System Conversions

To go from a smaller to a LARGER prefix, move the
decimal point to the left
 First write prefixes as powers of ten
 Find the differences in powers of ten
 Move the decimal point as many places to the left as
the difference in powers of ten
Example:
2.54 cm = _0.0000254_kilometers
Name
Symbol
Numerical
Value
Power of
Ten
megakilohectodecaBasic
Units
M
k
h
da
meters,
liters,
1,000,000
1,000
100
10
grams,
seconds
106
103
102
101
100
deci
centimillimicro-
d
c
m
µ
0.1
0.01
0.001
0.000001
10-1
10-2
10-3
10-6
TRY THIS USING THE
POWER OF TEN METHOD
1000 mg = __1___ g
Step 1: Determine if you are going from LARGER to smaller or
smaller to LARGER
Step 2: Determine the differences in powers of ten
Step 3: Move the decimal point the amount of places that was
determined in steps 1 & 2.
Name
Symbol
Numerical
Value
Power of
Ten
megakilohectodecaBasic
Units
M
k
h
da
meters,
liters,
1,000,000
1,000
100
10
grams,
seconds
106
103
102
101
100
deci
centimillimicro-
d
c
m
µ
0.1
0.01
0.001
0.000001
10-1
10-2
10-3
10-6
TRY THIS USING THE
POWER OF TEN METHOD
.15 L = ___150_____ ml
Step 1: Determine if you are going from LARGER to smaller or
smaller to LARGER
Step 2: Determine the differences in powers of ten
Step 3: Move the decimal point the amount of places that was
determined in steps 1 & 2.
DIMENSIONAL ANALYSIS
Allows one to change from one unit to
another
 Units are always used in all calculations
RULES:
 Set up equality in fraction form.
 Lined up such that units used on the top
and bottom of neighboring fractions are
alternated so that units cancel.

Examples
Given: 1 in = 2.54 cm
1 ft = 12 in
 How many cm are in 5 inches?
5 in
× 2.54 cm = 12.7 cm
1
1 in
 How many inches are in 27 feet?
27 ft
× 12 in = 324 in
1
1 ft