Dimensional AnalysisBridge The FactorLabel Method Uses Conversions Factors

Dimensional Analysis-”Bridge” • The “Factor-Label” Method • Uses Conversions Factors (things that are equal) to cancel units. • Units, or “labels” are canceled, or “factored” out

Dimensional Analysis • Steps: 1. Identify starting & ending units. 2. Line up conversion factors so units cancel. 3. Multiply all top numbers & divide by each bottom number. 4. Check units & answer.

Lining up conversion factors: 1 in = 2. 54 cm =1 2. 54 cm 1 in = 2. 54 cm 1= 1 in

What is a conversion factor? Any fraction (ratio) in which the numerator is equal to the denominator. • 12 inches = 1 foot • 12 inches: 1 foot • 12 inches 1 foot OR OR

Creating a “Bridge” • A bridge will take us from unit to the next… • Ex: How many inches are in 5 feet? 1. What is our beginning unit? 2. What is our ending unit? 5 feet 3. What do we need to convert? inches

Lets try a practice problem…. • There an average of 124 zombies per square mile. If the Walking Dead group has traveled a total of 7 square miles, how many zombies have they encountered? • What if Rick kills 40 zombies per square mile, how many did he kill?

Now a real measurement • Mrs. Wooley walks 2. 8 miles per day. How many centimeters does she walk per day? How many centimeters does she walk in a month? • A person drinks eight glasses of water a day. Each glass contains 300 m. L. How many m. L of water will a person drink in 1 year?