Introduction to the
Metric System
Symbols
Prefixes
Converting Within the Metric System
Metric System
Usain Bolt won the gold
medal in the 100 meter
men’s track final of the
2008 Olympic games
held in Beijing, China.
Dawn Harper won the gold
medal in the 100 meter
women’s hurdle’s final at
those same Olympic
games.
Metric System
But how far is 100 meters?
How far is 10 meters?
What about 10 feet?
Can you easily figure out how far 10 feet
is, but have trouble knowing how far 10
meters is?
Metric System
You are not alone!
Measuring in metrics is
something we are not used to
doing.
In the United States, we use the
English system of measurement:
pounds, feet, inches, miles,
gallon, pint, etc.
Metric System
However, scientists around the world use the International
System of Measurements, (SI) or Metrics, to measure
distances, volumes, masses, and temperatures.
In fact, most countries
use the SI system of
measurement.
The countries in red are
NOT using the metric
system as a standard
measurement system.
Metric System
If you travel to France, the
distances and speeds marked on
the road signs will be in
kilometers, not in miles.
You would
buy milk
measured in
liters
Metric System
You may be used to
buying water and soda
in liters, so you are
already using the metric
system!
Metric System
Use your index finger to
measure the width of
your desk.
How many fingers wide is it?
Ask a classmate how many fingers wide their desk is.
Metric System
Do all of the desks in
your classroom look
like they are the same
width?
Did everyone arrive at
the same or different
answers?
What would the world
be like if we all used
our index fingers to measure
length?
Why do you think it is
important to have a
standard system of
measurement?
Metric System
Try converting 18 inches into feet.
How about 14 ounces into pounds?
The English system is not easy to use.
Metric System
Scientists need a standard system of
measurement that is easy to use and
convert measurements.
Fingers will not do!
The English system is confusing!
Using the same measuring system by
everyone world-wide allows for
uniformity of measurements.
Metric System
The metric system is based on the number
10. It is easy to use because each
measurement can be converted by simply
multiplying or dividing by a factor of 10.
Metric System
Look at the chart below to see the basic
metric units and their symbols.
Measurement
Unit
Symbol
Length
meter
m
Mass
gram
g
Volume
liter
L
Temperature
Kelvin (or Celsius)
K (C)
Metric System
Meter, Liter, and Gram
are all base units.
Prefixes are used with the
base unit of measurement
and indicate which multiple of
10 is being used.
Kilometer, milliliter, and
centigram are examples of
metric units that use prefixes.
Metric System
Here are some commonly used prefixes in the metric
system. Notice the multiplying factors are all based
on the number 10.
Prefix
Symbol
Multiplying
Factor
Giga
Mega
Kilo
Hecta
Deka
Deci
Centi
Milli
Micro
Nano
G
M
k
h
da
d
c
m
u
n
1,000,000,000
1,000,000
1000
100
10
0.1
0.01
0.001
0.000001
0.000000001
Metric System
The basic unit of length is meter.
A meter is about the length of a yard in the English system.
The length of a room or the length of a hallway would be
measured in meters.
A centimeter is one-hundredth (1/100) of a meter.
The length of your finger or your pencil would be measured
in centimeters.
Metric System
Use a metric ruler or a meter
stick to measure length in the
Metric System.
Metric System
The basic unit of mass is kilogram.
A kilogram is about 2.2 pounds.
The mass of one of your large textbooks may be about 1
kilogram.
A gram is one-thousandth of a kilogram.
Pencils, candies, and cereal can be measured in grams.
Metric System
Use a balance or scale to
measure mass in the Metric
System.
Metric System
The basic unit of volume is the Liter.
A liter is about 34 ounces, or about 1/4 of a gallon.
The volume of a large bottle of soda is 2 liters.
A milliliter is one-thousandth (1/1000) of a liter.
A glass of water, a bottle of drinking water, and a jar of
spagetti sauce can be measured in milliliters.
Metric System
Use a graduated cylinder to measure
volume in the Metric System.
Metric System
One of two units may be used in the Metric
System when measuring temperature.
0 degrees Celsius =
freezing point of water
0 degrees Celsius =
273 Kelvin
37 degrees Celsius = body
temperature
310 Kelvin = body
temperature
Metric System
Once you learn how to measure in the Metric
System, you will need to convert from one unit
to another on occasion.
For instance, you may have a balance that
measures in grams, but your lab directions call
for you to record the mass in kilograms. You
will need to know how to convert the units.
Metric System
An easy way to convert between the commonly
used measurements is to simply move the
decimal.
But…
How many places do you move the decimal? Which
direction do you move it?
Here’s an easy method to converting measurements
within the Metric System which uses a mnemonics
chart.
Metric System
1000
100
10
1
1/10
1/100
1/1000
Here are some prefixes and their
corresponding values.
Reading from left to right: each prefix is 10 times smaller
than the value on its left.
Reading from right to left: each prefix is 10 times larger than
the value on its right.
Metric System
1000
100
10
1
1/10
1/100
1/1000
A kilometer is 10 times longer than a
Hectameter.
A kilometer is 1000 times longer than a meter
Metric System
1000
100
10
1
K
H
D
B
King
Henry
Died
By
1/10
1/100
1/1000
D
C
M
Chocolate
Milk
Drinking
A mnemonic can help you with conversions within
the Metric System.
Each letter of the mnemonic begins with the first
letter of the metric prefix.
Metric System
1000
100
10
1
1/10
King
Henry
Died
By
Drinking
1/100
1/1000
Chocolate
Milk
You will always be able to rebuild this
chart if you memorize the mnemonic!
Metric System
Since the Metric System is based on factors of 10,
we need only worry about moving the decimal
when converting between metric measurements.
Let’s try a conversion:
How many milliliters are in 1.25 Liters?
OR
1.25 L = ? mL
Metric System
1000
100
10
1
1/10
King
Henry
Died
By
Drinking
1/100
1/1000
Chocolate
Milk
Start with the mnemonic:
King Henry Died By Drinking Chocolate Milk.
Now add the prefixes that start with the first letter of the
mnemonic. They will be in the correct order!
Each Prefix along the
chart is a “Place” or
“Spot”.
Metric System
1000
King
100
10
1
1/10
Henry
Died
By
Drinking
1/100
1/1000
Chocolate
Milk
Now we are ready to make the conversion: 1.25 L = ? mL
Step 1: Since Liter has no prefix, we will place our pencil
on the “Base-No Prefix” spot.
Step 2: Find “Milli-” on the chart.
Metric System
King
Henry
Died
By
Drinking
Chocolate
Milk
Step 3: Start at “Base-No Prefix” and jump your pencil to the
right towards “Milli-”. You moved 3 places to the right to arrive
at “Milli”.
Step 4: Now move the decimal in 1.25 L to the right 3 places.
This matches what you just did on the chart.
Metric System
Move the
decimal to the
right 3 places.
Add a zero in the
last place.
You need not keep the decimal
visible – it is understood to be to the
right of 1250 ml.
Metric System
1000
100
10
1
1/10
1/100
Try another conversion: 247 meters = ? kilometers
Follow the previous steps:
Place your pencil on “Base-No Prefix” and move to
“Kilometers” by jumping 3 spaces to the left.
1/1000
Metric System
Now move the
decimal point
3 spaces to the
left.
Add a zero in front
of the decimal.
Remember:
Meter – m,
The decimal is
understood to be to
the right of ‘7’.
kilometer – km
Metric System
King
Henry
Died
Convert 56.2 cm to mm.
By
Drinking
Chocolate
Milk
Move the decimal
one place to the
right.
Metric System
King
Henry
Died
By
Drinking
Convert 467.0 centigrams to grams
You see that the decimal needs to
move to the left two places.
Chocolate
Milk
Metric System
1000
100
10
1
1/10
King
Henry
Died
By
Drinking
1/100
Chocolate
1/1000
Milk
Draw the above chart on your paper and try
these conversions:
1. 93.2 mL = ? L
2. 845.34 g = ? Kg
3. 0.56 m = ? cm
Answers are
revealed on the
next slide.
Metric System
1000
King
100
10
Henry
Died
Answers:
1. 93.2 mL = 0.0932 L
2. 845.34 g = 0.84534 Kg
3. 0.56 m = 56 cm
1
1/10
By
Drinking
1/100
Chocolate
1/1000
Milk
Remember to add zeroes
as placeholders where
necessary.