Transcript Metric System - Longview School District

Metric
System
Part 1
The Metric System
• Is a system of
measurement.
• Is also known as the
“S.I. System”.
(System International)
Metric System
Quantity
Unit
Unit Symbol
Distance
meter
m
Mass
gram
g
Volume
liter
L
Time
second
s
Temperature
degrees celsius
oC
Prefixes
every student should know…
Prefix
Symbol
Means..
Example
milli-
m
thousandth
mL
centi-
c
hundredth
cg
kilo-
k
thousand
km
Tools of Measurement
Quantity
Unit
(unit symbol)
Tool
Distance
meter
(m)
meterstick or
ruler
Mass
gram
(g)
balance
Volume
liter
(L)
graduated
cylinder or
beaker
WHY USE METRIC?
Benefits of
the Metric
System:
• It uses the decimal
system (10’s!)
• It is an International
Standard.
• The units relate to
each other.*
*(More on this later!)
kilo, centi, milli
• Be able to give your
answer using any of
these prefixes!
For example:
• A snowboard is
– 1.85 m
or
– 185 cm
or
– 1850 mm
How do you do that?
Problem:
How many centimeters is 1.5 meters?
There are many ways to solve this problem. One way is
Common Sense:
1. The Metric System prefixes work by multiples of 10.
So, the answer must be found by just moving the decimal
point. Some possible answers are:
15cm, 150 cm, 1500 cm,
0.15 cm, 0.015 cm
2. Which of these are reasonable answers?
Does the measurement
make sense?
– 1cm = width of a fingernail
– 1 g = mass of a push pin
– 1 mL = ~20 drops of water
Practice Guessing:
1.5 m
12 cm
=
=
150 cm
0.12 m
0.295 m =
295 mm
0.8 m
80
=
cm
Metric
System
Part 2
Metric System
Quantity
Unit
Unit Symbol
Distance
meter
m
Mass
gram
g
Volume
liter
L
kilo, centi, milli
• Be able to give your
answer using any of
these prefixes!
For example:
• A snowboard is
– 1.85 m
or
– 185 cm
or
– 1850 mm
How do you do that?
Practice Guessing:
1.5 m
12 cm
=
=
150 cm
0.12 m
0.295 m =
295 mm
0.8 m
80
=
cm
Metric
Staircase.
• Move up a step (left):
…decimal moves left
k - kilo
h - hecto
da - deca
(no prefix) -base
base
just meter, liter, or gram
• Move down a step (right):
…Decimal moves right
d - deci
c - centi
centi
m - milli
Practice
1500 cm
=
15
m
0.012 m
=
12
mm
29,500 cm = 0.295 km
0.08 km
=
8000 cm
Does the measurement
make sense?
– 1cm = width of a fingernail
– 1 g = mass of a push pin
– 1 mL = ~20 drops of water
Metric System
Quantity
Unit
Unit Symbol
Distance
meter
m
Mass
gram
g
Volume
liter
L
What is mass?
• Mass is a
measure of the
amount of a
substance.
•Mass is not weight
•Mass is not “how much space something takes
up”; (that’s what volume is!)
Mass versus Weight
• Your mass is the
same everywhere in
the universe
•Your weight is less on the
moon than it is on earth,
because weight depends on
gravity.
link
Tools of Measurement
Quantity
Unit
(unit symbol)
Tool
Distance
meter
(m)
meterstick or
ruler
Mass
gram
(g)
balance
Volume
liter
(L)
graduated
cylinder or
beaker
Practice Prefixes, Methods of
Metric Conversion
• Prefixes are Universal
– cg,cm,cL, etc.
• Review Methods:
– Common sense
– Metric Staircase
• Introduce Method:
– Dimensional Analysis
• Practice with balances
• Practice with common
sense conversion and
then staircase
conversion using
grams and kilograms,
etc.