THE METRIC SYSTEM!!
The universal language of science
What is the difference
between metric and standard
(English) System of measure?
 The English system uses a base of
12
 The Metric system uses a base of
10
Why does the United States
still use the English system?
 Convenience? Maybe we just don’t want to
change because we would have to learn
some new stuff
 Cost? It would cost a lot of money: Think
about roadsigns, containers, cars, foods, etc
Probably a little of both…
OK…Here we go
 This is a much easier way to do
calculations, and make conversions:
 Try these 2 calculations one in the
English system and one in metric
 Convert 7,899 inches to miles
 Convert 7,899 centimeters into kilometers
First the English measure
 7,899 inches/12inches in a foot
658.25 feet
• 658.25 feet/5,280 feet in a mile
.12466856060 of a mile
• All that just to make 2 conversions????
Now the Metric method
 7,899 centimeters to kilometers…
 Ready? Go… Move the decimal 5 places
to the left. That’s it.
.07899 kilometers
Start with base units
 Base units are what we multiply by the
prefix to arrive at a new quantity. It
doesn’t matter what it is…just apply
the prefix to the base unit.
 Here are some common base units
Mass=grams
 Grams-How much is a gram? About a
penny.
Volume
 2 ways to do this
Liters-usually liquid or gas containers
Meters cubed: B X H X W = M3
Length=meters
 Meters: The length of a guitar is
roughly one meter.
Temperature
 Celsius, or Centigrade: How do you covert
Farenheit to Celsius?
 98.6F is roughly equal to 37C
Prefixes
 Now that we have the base units, we
need to know what to do with them. In
the metric system, we add a prefix to a
base and multiply the number
represented by the prefix by one base
unit… Here we go
Prefix names and numeric
meanings
 Here are some fun ones
 Yotta000
 Zetta Exa Peta Tera Giga Mega-
Y
10 24
1 000 000 000 000 000 000 000
Z
E
P
T
G
M
10 21
10 18
10 15
10 12
10 9
10 6
1 000 000 000 000 000 000 000
1 000 000 000 000 000 000
1 000 000 000 000 000
1 000 000 000 000
1 000 000 000
1 000 000
More useful prefixes









kilohectodekaUnit
decicentimillimicronano-
k
h
D
?
d
c
m
mu
n
10 3
10 2
101
100
10 -1
10 -2
10 -3
10 -6
10 -9
1000
100
10
1
0.1
0.01
0.001
0.000 001
0.000 000 001
Putting it together
 Add the prefix to the base:
 Example how many grams is 25 kG
 Kilo is 1000
 25 is 25 (duh)
 So this is 25,000 grams
Conversions
 Since everything is base 10, all you have to
do is move the decimal:
 Convert 3899 mL to L
 Look at the prefix scale and move the decimal the
same direction as the prefix
 Since we are moving from milli to unit, move the
decimal 3 spaces to the left:
 3.899 L
Practice

1)
2)
3)
Convert
23 mg to dg
45 DL to mL
9966 mm to km
kilo- k
hecto- h
deka- D
Unit ?
deci- d
centi- c
milli- m
micro- mu
001
nano- n
000 001
Going up=decimal to the left
Going down=decimal to the right
10 3
10 2
101
100
10 -1
10 -2
10 -3
10 -6
1000
100
10
1
0.1
0.01
0.001
0.000
10 -9
0.000
Answers
1) 23 mg = .23 dg
2) 45 DL = 450000 mL
3) 9966 mm = .009966 km
Celsius
 In Science and really in the rest of the
world we use the Celsius scale, named
after Anders Celsius (1701-1744).
This is based on:
freezing = 0 degrees C
boiling = 100 degrees C…
 Unfortunately these temperatures can
be expressed as negatives which
makes them difficult to do calculations
with, sooooo……
Kelvin Scale
 The Kelvin scale is more useful in
science because there are no
negative temperatures. This is based
on the absolute zero concept. That is
the temperature at which all molecular
motion stops. This is 273.15  below
zero Celsius. That is cold!!! This is
about 460 degrees below zero
Farenheit