Dimensional Analysis -Dimensional analysis is a way to convert from one type of unit to another ex. miles to kilometers or cups to milliliters lbs to dollars or miles to dollars -Start by beginning with a known value ex. ½ dozen eggs -Look for the conversion factor: ex. 1 dozen = 12 eggs can be written  _1 dozen_ or _12 eggs_ 12 eggs 1 dozen -Multiply each so that the known unit is on the bottom (denominator) of the conversion factor: _½ dozen_ × _12 eggs_ 1 1 dozen _½ dozen_ × _1 dozen_ 1 12 eggs

Dimensional Analysis -We want the known unit on the “bottom” (or denominator) so that we can cancel units out and we are left with the unit we want One more example: _½ dozen_ × _12 eggs_ = 6 eggs 1 1 dozen _2 dozen_ × _12 eggs_ = 24 eggs 1 1 dozen

Dimensional Analysis Practice 1. How many minutes are in a year? 2. I took a trip up to Vancouver, Canada and I noticed that the speed limit was different there. It was 100 km/hr. How fast was I going? How many miles are in 100 km? (0.62 mi = 1 km) 3. I’m trying to buy some ground beef at the supermarket. My recipe calls for 2 lbs. to make my chili. It costs $3.50 per lb. How much will that cost? 4. My car gets about 30 mi/gallon on the freeway. I’m going to drive to Los Angeles, which is about 380 mi. Can I drive down there in one tank of gas (12 gallons) if I fill it all the way to the top? 5. You're throwing a pizza party for 15 people and figure each person might eat 4 slices. How much is the pizza going to cost you? You call up the pizza place and learn that each pizza will cost you $20 and will be cut into 12 slices. You tell them you'll call back. Do you have enough money?