What is SI?
Slide 1
Objective
I can:
· Explain the importance of the International System of Units
· Convert between SI units
Slide 2
What is SI?
To make sharing information easier, most of the world uses the SI of measurement. SI,
which stands for Système Internationale d’Unités, is a standard for measuring mass,
length, volume, and other quantities. It is used by all scientists to avoid the confusion of
comparing data that is based on different measuring systems. Three common SI units
are listed below. Obviously, these three units are not suitable for all measuring needs.
Quantity
Unit
Symbol
length
meter m
volume
liter
L
mass
gram g
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What is SI?
Slide 3
Procedure
To convert between SI units, first find the prefixes of your numbers on your science
reference sheet on the back cover of your IAN.
If you are
slide your
If you are
slide your
converting from a smaller prefix to a larger prefix (moving up the chart),
decimal to the left the number spaces you are moving.
converting from a larger prefix to a smaller prefix (moving down the chart),
decimal to the right the number spaces you are moving.
Resources
SI Reference
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What is SI?
Slide 4
Sample Problem #1
Convert 500 decimeters (dm) to kilometers (km).
Step 1: Find the prefixes of the numbers.
decimeters to kilometers
Step 2: Notice that you will move up the chart (left) four places when converting from
deci- to kilo-. Therefore, you will slide your decimal 4 places to the left.
500 decimeters (dm) = 0.05 kilometers (km)
Slide 5
Sample Problem #2
2.5 centiliters (cL) is how many milliliters (mL)?
Step 1: Find the prefixes.
centiliters to milliliters
Step 2: Because you move down the chart one place to the right, when converting from
centi- to milli-, move your decimal one place to the right.
2.5 centiliters (cL) = 25 milliliters (mL)
Slide 6
True or False?
12 hg = 1.2 kg
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What is SI?
Slide 7
True or False?
12 hg = 1.2 kg
TRUE!
Slide 8
25 mm = ??? cm
A) 25
B) .025
C) 2.5
D) 250
Slide 9
27 kg = 270,000 ???
A) dL
B) dg
C) cm
D) dag
4
What is SI?
Slide 10
Summary
You have learned both the importance of SI and how to convert between SI units.
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