1. Units of Measurement Conversion Factors
Unit Conversions
Units of Measurement
Conversion Factors

2. SI Measurements The international system of measurement
The metric system
A set of agreed-upon standard units of measurement
Numbers are written without commas
not 1,000.00
Some countries use commas to represent a decimal point.

3. SI Units
Prefixes are added to base units to represent larger or smaller quantities and measurements
Base Units:
Mass = grams (g)
Volume = Liters (L) or cubic meters (m3)
Length = meters (m)
Time = second (s)
Temperature = Kelvin (K)
Amount of a substance = moles (n)
(1 mL = 1 cm3)

5. Conversion factors
A ratio (fraction) that shows the equality of two different units.
Used to convert from one unit to another
Written as FRACTIONS
Can be written upside down too!
Dimensional Analysis = a math technique for solving problems that involve measurements

6. Example 4 quarters = 1 OR 1 dollar = 1 1 dollar 4 quarters
We know that 4 quarters = 1 dollar
Conversion factors:
4 quarters = 1 OR 1 dollar = 1
1 dollar quarters
1 quarter = 1 OR dollar = 1
0.25 dollar 1 quarter
If I have 27 quarters, how much money do I have in dollars?
27 quarters x 1 dollar = 27 ÷ 4 = $6.75
4 quarters

7. Steps for solving problems:
1. Write down the number given to change (the value in the question/problem).
2. Drop the unit that goes with the number to the bottom of the next fraction.
3. Each ratio (or fraction) you multiply is a known quantity (like 4 quarters=1 dollar).
4. Keep multiplying by ratios that you know until you come to the unit you want to end with.

8. Example 1
Convert 180 miles into feet.
Given: 1 mile = 5,280 feet

9. Example 2
Convert 27 days into seconds.
What givens do we know?

10. Example 3
If prefixes are used, always go back to your base unit and kick off from there.
Ex: Convert 22 kilograms into centigrams.

11. Sample Problems
Complete the following and determine what kind of measurement it represents (mass/volume/etc.):
10.5 g = ______ kg
1.57 km = ______ m
3.54 μg = _________ g
1.2 L = _______ mL
932 seconds = ______ minutes
548.6 mL = ______ cm3

12. Unit Conversions Worksheet
For each problem, follow the guidelines:
--Keep dropping your unit!
--Watch parentheses!
--Include units in the answer!
--Prefix with base only

13. Units m=meter min=minutes s=seconds mi=miles gal=gallons g=grams
k=kilo--____

14. Multi-Step Problem 12.4 cm=_____ km 133 mL=_____ gallons
64.33 mi= _____ yards