1. Measurements and Dimensional Analysis

2. Why do we have standard measurements?
A measurement consist of two parts
Number
Scale
Two Major systems
English system
Used in the United States
Pounds
Feet
gallons
Metric system
SI System – based on the metric system and units derived from it

3. SI Unit of Measurement Quantity SI Unit Symbol Length Meter m Volume
Cubic meter
Liter m3 L
Mass
Kilogram Kg
Density
Grams per cubic centimeter
g/cm3
Temperature
Kelvin K
Time
Second s

4. SI Prefixes Conversion Factor: a ratio of equivalent measurements
109
106
1000
100 10
0.1
0.01
0.001
10-6
10-9
Conversion Factor: a ratio of equivalent measurements
1 m = 10 dm
1 m = 100 cm
1 m = 1000 mm
1 liter = (1 dm)3 = (10cm)3 = 1000cm3 4

5. Conversion Factors Derived Units
Combination of SI units from Derived units
Conversion Factors: ratio derived from the equality of two different units that can be used to convert from one to the other
Use units to help derive and cancel (algebraic) 5

6. Solving Problems using Dimensional Analysis
Analyze
Identify given
Identify needed
Plan
Use units to cancel
Compute
Plug in #s
Evaluate
Examine to determine if reasonable

7. Sample Problems
m to km cm3 to mL hours to seconds L to mL kg to g cm3 to L 7. 56,000 μg to kg km to mm ***Always show your work***