1. Nature of Science
Metric System-International System of Units
(SI)

2. Learning Targets: Use appropriate tools and equipment for measuring
Use the metric system for measuring
Use the “ladder method” and dimensional analysis to convert values between metric and English units

3. The Metric System
Standardized system of measurement used by all scientists worldwide.
Based on units of 10
Similar to our monetary system:
10 cents = dime
100 cents = dollar dimes = dollar

4. In the English system you have to remember so many units numbers . . .
12 inches in a foot
3 feet in a yard
5,280 feet in a mile
16 ounces in a pound
4 quarts to a gallon
In the SI System you only have to remember one number and a few basic units

5. Basic Types of Measurement
Length: measures distance between objects
Volume: measures the amount of space something takes up
Mass: measures the amount of matter in an object
Temperature: measures molecular movement
in an object

6. Measurement System Comparisons
BASIC UNIT
ABBREVIATION
LENGTH
Meter m
VOLUME
Liter L
TEMPERATURE
Celsius °C
MASS
Gram g
TIME
Second
s, sec
All Measurement systems have standards. Standards are exact quantities that everyone agrees to use as a basis of comparison.

7. 1 Liter
1 Gram
1 Meter

8. Weight vs. Mass Measure of the force of gravity on an object
Measure of amount
of matter in an object
NOT affected by gravity

9. Weight vs. Mass Weight and Mass are related, but NOT the same.
Weight can change depending on location
Mass is constant regardless of location
The greater the mass, the larger the pull of gravity.
The larger the pull of gravity, the greater the weight

10. Metric System Prefixes
Kilo
1000
Hecto
100
Deca 10
Base Unit
g, m , L 1
Deci .1
1/10
Centi
.01 1/100
Milli
.001 1/1000
The Base Unit is the determined by the type of measurement being made. (mass, volume, or length)
The same prefixes are used regardless of the the measurement type being made length, mass, or volume.

11. Milli (m)
Means 1/1000
1000 “milli’s” make a whole unit
Centi (c)
Means 1/100
100 “centi’”s make a whole unit
Deci (d)
Means 1/10
10 “deci’s” make a whole unit
Deka (dk)
Means 10
There are 10 whole units in a “deka”
Hecto (h)
Means 100
There are 100 whole units in a “hecto”
Kilo (k)
Means 1000
There are 1000 whole units in a “kilo”

12. µ - micro- one millionth
ex. Micrometer or micron
n nano one billionth

13. Abbrev Word Meaning
mm millimeter one thousandth meter cg kL cm mL mg km kg

14. Abbrev Word Meaning
mm millimeter meter (thousandth)
cg centigram gram (hundredth)
kL kiloliter liters
cm centimeter meter (hundredth)
mL milliliter meter (thousandth)
mg milligram gram (thousandth)
km kilometer meters
kg kilogram grams

15. You can write the conversion as a fraction that equals 1: 1000 m 1 km
Let's start with a simple example:
Convert 3 km to m (3 kilometers to meters). There are 1000 m in 1 km, so the conversion is easy, but let's follow a system:
You can write the conversion as a fraction that equals 1:
1000 m
1 km
= 1 km
1 km
= 1

16. Let's start with a simple example:
Convert 3 km to m (3 kilometers to meters). There are 1000 m in 1 km, so the conversion is easy, but let's follow a system:
3 km x 1000 m
1 km
Conversion factor
= 3000 km · m = km · m = 3000 m
1 km 1 km

17. How many meters are in 260 centimeters?
Example #2:
How many meters are in 260 centimeters?
1 m
100 cm
= 260 cm x 1 m
100 cm
260 cm =
= 2.60 m
Conversion factor
Divide this time!!

18. What if we need to go from milligrams (mg) to kilograms (kg)
What if we need to go from milligrams (mg) to kilograms (kg)? One extra step!
Example #3: How many kilograms in 330 miligrams?
330 mg = 1 g = 1 kg = mg x 1 g x 1 kg = kg
1000 mg g mg x 1000 g
Two conversion factors must be used!
You need to start from the base unit!

19. Let’s try going from metric units to standard/English units
Example #4: How many kilograms are in 3 pounds?
You need a conversion factor! pound = 454 grams

20. Things to Remember All measurements need a number and a unit!
Basic units of Measurement (meter, liter, gram)
Metric prefixes and values
How to convert units

21. Metric Measurement: Length
Length is the distance between two points.
Does not matter if it is width, height, depth, etc. All are length measurements.
The basic unit of length in the SI System is the meter.
The meter is about the length of the English yard (3 feet).
Area is a variation of a length measurement.
Area is length x width.
Expressed in units2 (m2, cm2, mm2 etc.)

22. Metric Measurement: Mass
Mass is a measurement of the amount of matter in an object.
Basic unit of mass is the gram. There are grams in one pound.
Weight and mass are related, but NOT the same.
Weight is the pull of gravity on an object
The greater the mass, the larger the pull of gravity.

23. (L)ength x (W)idth x (H)eight
Metric Measurement: Volume
Volume is a measurement of the amount of space something takes up.
The basic unit used for volume is the liter. This unit is used for the volumes of liquids.
Volumes of solids are figured using this formula:
(L)ength x (W)idth x (H)eight
cm x cm x cm = cm3
Objects without a definite length, width or height (a rock for example), can use water displacement to determine volume NOTE: 1 ml = 1 cm3

24. Metric Measurement: Temperature
Temperature is a measure of the kinetic energy of the atoms in an object.
Temperature is measured with a thermometer and measured in Celsius or Kelvin.
Celsius ranges from 0 (freezing) to 100 (boiling).
The Kelvin scale begins at absolute zero, or 0 K. At 0 Kelvin no more heat can be removed from an object.
To convert to Kelvin you add 273 degrees to the Celsius reading.
Freezing in Kelvin is 273 K, boiling is 373 K.

25. Which is heavier . . . The formula for density is:
Density is how much matter is in something (mass), compared to the amount of space it takes up (volume).
Which is heavier . . .
A kilogram of feathers or a kilogram of lead?
They are both one kilogram so they weight the same, but it takes more feathers than lead to equal one kilogram!
The formula for density is:
Mass (grams)
divided by
Volume (cm3)
So the unit for density is g / cm3
Every substance has a density, and that density always remains the same.
Density can be used to figure out what an unknown substance is.
The density of water is 1 g / cm3
Which one takes up more space (volume)?
We say the lead is more dense than the feathers.