International System of Units
Sep 29
Learning Target: I can
convert measurements using the
metric system.
Catalyst: What are the metric
units used to measure volume
and mass?
• Curriculum Night for Parents:
Wednesday, September 30th, 6 p.m.
• Metric System and measuring test:
Friday, October 2nd
• Science Tutoring – Mon & Thurs 2:30 – 3:30.
• Your science journal must be up to date to
be eligible to retake an assessment.
What is measurement?
In science, the ability to describe an observation
is an important skill.
Often, a scientist uses a
measurement to describe
an observation.
A scientific measurement
includes a number and a
unit.
Observation: This shell is 65mm.
number
unit
What is the International
System of units?
Another name for the metric
system is the International
System of Units (SI).
SI units are used for all
scientific measurements.
How can we make very large or small
measurements easy to work with?
Some scientific numbers are much smaller
or much larger than those we use in
everyday life.
Measurements that are very big or very
small can be confusing to work with.
There are two ways that scientists can
make working with very large or very small
numbers easier: prefixes and scientific
notation.
What is a Prefix?
• A prefix is one or more letters
in front of a word to change its
meaning.
• Example: reschedule, outrun,
semicircle
What is an SI Prefix?
• An SI prefix is used to write an
SI unit that is larger or smaller
than a base unit.
• Example: kilo means 1000 so a
kilometer is 1000 meters
Meters
Liters
Grams
• Example: kilo means 1000 so a
kilometer is 1000 meters
SI Conversions
• Metric units are very nice to work with,
•
•
since they are all multiples of ten (or a
hundred, or one-tenth, etc) of each other.
You can convert between the various
different sizes by merely moving the
decimal point the correct number of
places.
Video: https://www.youtube.com/watch?v=BL8IcotPv4Q
King Hector Died
Kilo
Hecto
Deka
Unexpectedly
Unit (meter, liter, gram)
Drinking Chocolate Milk
Deci
Centi
Milli
1
Ladder Method
2
KILO
1000
Units
3
HECTO
100
Units
DEKA
10
Units
DECI
0.1
Unit
CENTI
0.01
Unit
Meters
Liters
Grams
4 km = _________ m
How do you use the “ladder” method?
1st – Determine your starting point.
2nd – Count the “jumps” to your ending point.
3rd – Move the decimal the same number of
jumps in the same direction.
MILLI
0.001
Unit
Starting
Ending Point
Point
How many jumps does it take?
__. __. __. = 4000 m
4.0
1
2
3
Move decimal to the
RIGHT when moving
to a SMALLER prefix.
Move decimal to the
LEFT when moving
to a BIGGER prefix.
KILO
1000
Units
HECTO
100
Units
DEKA
10
Units
DECI
0.1
Unit
Meters
Liters
Grams
CENTI
0.01
Unit
MILLI
0.001
Unit
Try these conversions using the ladder method.
1 g 1 L = 1,000
1,600 mm
1000 mg = _______
_______ mL
160 cm = _______
14,000 m
14 km = _________
0.109 kg
109 g = ________
0.25 km
250 m = _______
Compare using <, , or =.
>
56 cm
6m
7g
>
698 mg