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The Metric System
and Metric Conversions
Why Use The Metric System?

It is neutral and universally understood.
 It uses standards that can be replicated
by scientists working in any nation.
 The decimal nature of the metric system
makes conversion between metric units
simpler.
 Prefixes serve as convenient modifiers
for metric units.
SI Units
QUANTITY
SI UNIT
UNIT SYMBOL
Length
meter
m
Liquid or Gas Volume
liter *
L
Solid Volume
cubic meter
m3
Temperature
Kelvin
K
Mass
gram
g
Amount
mole
mol
Time
second
s
*Not actually an SI unit, but commonly used.
Scientific Notation
A way to express very large and
very small numbers.

A form of shorthand.
 Write 2.03 x 1018 instead of
 2,030,000,000,000,000,000

These two numbers are identical; just
written a different way.
 Like 2 + 3 is the same as writing 5.
Scientific Notation
Powers of Ten
101 = 10
 102 = 10 x 10 = 100
 103 = 10 x 10 x 10 = 1000
 104 = 10 x 10 x 10 x 10 = 10,000
 105 = 10 x 10 x 10 x 10 x 10 = 100,000
 And so on...

Scientific Notation
Negative Powers of Ten





10-1 = 1/10 = 0.1
10-2 = 1/10 x 1/10 = 1/100 = 0.01
10-3 = 1/10 x 1/10 x 1/10 = 1/1000 = 0.001
10-4 = 1/10 x 1/10 x 1/10 x 1/10 = 1/10,000 = 0.0 001
And so on...
Prefixes

Positive powers of ten:
– kilo(k) = x 103 = x 1000
– Mega(M) = x 106 = x 1,000,000
– Giga(G) = x 109 = x 1,000,000,000

Negative powers of ten:
–
–
–
–
centi(c) = x 10-2 = x 0.01
milli(m) = x 10-3 = x 0.001
micro(μ) = x 10-6 = x 0.000 001
nano(n) = x 10-9 = x 0.000 000 001
Prefixes

Express 1 km in m.
– kilo = x 1000
– 1 kilometer = 1000 meters
 Express 1 mm in m.
– milli = 0.001
– 1 millimeter = 0.001 meter
Prefixes

1,000,000 phones = ???
– 1 Megaphone (get it?)

0.000 001 phones = ???
– 1 microphone

0.000 001 scopes = ???
– 1 microscope


Metric prefixes are even used in literature:
2000 mockingbirds =
– 2 kilomockingbirds
Prefixes
So many.
How can I remember which is which?
Centi
How many pennies
does it take to make up
a dollar?
1/100 of a dollar
What another name of a
penny?
Cent
More Money
There are two prefixes that start with D
Deca- 10
Deci-
1/10
When you see a D, think of a
dime
Because both of the d’s deal
with 10
And the smaller has the I, just like dime
We also can use time to help us
remember
10 years
Decade
100 years
Century
Micro- stands for 10-6
or 0.000001
or 1/1000000
Nanotechnology –
really, really small technology
Nano is 10-9
So, also think
nano = nine
Looking at mp3 players and
computers to remember other
prefixes
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•
•
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I have a 60 gig hard drive.
My old mp3 holds 512 MB of music.
My new iPod nano holds 8 GB
A blank CD-R holds 700 MB of music.
Mp3’s are about 5 MB
The iPod nano picture I used in this presentation
is 468 KB
KB = kilobyte = 1000 bytes
MB = megabyte = 1000 KB or 1000000 bytes
Gig = gigabyte = 1000 MB or 1000000000 bytes