1. Working with the customary system Customary Units of Measure

2. What do we hope to accomplish? We will convert between customary measures We will try to use a new tool, a conversion factor, in dimensional analysis

3. We will choose appropriate measures, solve applications, and convert within the customary system.*

4. Choosing Appropriate Measures a.Weight of a truck b.Length of a hallway rug c.Length of a swimming pool d.Weight of a baby e.Length of a pencil f.Capacity of an eyedropper g.Weight of a paperclip h.Volume of a baby bottle i.Distance to Australia j.Length of a sports field tons feet or yards pounds inches fluid ounces ounces fluid ounces miles yards

5. Measurement Conversion Everyone has their own way of converting within a measurement system. I have processes that are comfortable to me, personally…. You do, too. Using something called a “conversion factor” is a technique that is useful when a comfortable method doesn’t occur to you…….. Using a conversion factor to convert measures within the same system, or between measurement systems, is called dimensional analysis. We will practice this new method. You WILL hear it again in future math classes…..don’t be afraid to try something new.

6. What is a conversion factor???? A conversion factor is a ratio of two different units that are equal to each other. If I were converting gallons to quarts, I would use the conversion factor of Look back at the customary measures chart. Conversion factors come from “things” that are equal to each other! With conversions factors, the order in which you write the two, equal measures depends on how you want to set up your conversion problem!

7. What is a conversion factor???? 10 qt. = ? gallons Let’s use the text example and convert 10 qt to gallons…..yes, I know it’s 2 ½ gallons. The conversion factor you write is equal to 1. You choose the order in which you write the units based on what will cancel with the unit you are converting. This is sometimes called a “unit multiplier.” Let’s look at this process in detail….. First you write the measures you have……. Next you create a ratio (unit multiplier) that contains the measure you have and the new unit you are wanting…..Solve….. 5 2

8. Practice the Process We are to convert 14 oz. into lbs. We want to write a conversion factor = 1 that shows the relationship between ounces and pounds. The ounces cancel out. We are left only with pounds and a fraction to simplify.

9. We are to convert 14 inches to feet. Our conversion factor for ft/inches is……. Cancelling our like units leaves us with a fraction to simplify. We are converting pints to quarts. We have 14 pt. Our conversion factor for pt/quarts??? Cancelling our like units and simplifying what is left gives us our result.

10. 1 gallon 4 quarts = 8 pints = 16 cups = Customary measures of capacity often give people problems. If you do not use these regularly, they are often difficult to remember. The basic ones to know are:

11. Application At Store A, cashews cost $15.99 for a 4 ¼ lb. bag. Store B charges the same price for a 76-oz. bag. What is the better buy? At which store do you get more for your money? The price is the same, so let’s see how many ounces are in the 4 ¼ lb bag. We already have the ounces for store B. Conversion factor for pounds/ounces? 4 Store A give you 68 ounces. Store B is the better buy.

12. Complete each equation: 3 ½ lb = _____ oz 3 ½ yd = _______ft. 3 ½ pt. = _______c 8 56 10 ½ 7

13. Conversion factors are most helpful when converting between systems. 1in = 2.54 cm. If I wanted to know how many cm were in 2 feet, I could use conversion factors…. This could then be converted into meters, mm, or any other measure…… While you might not see a need for this skill now, the ability to set up a conversion factor will be important in future math classes. Try it whenever possible.

14. Small Group Practice p. 255 (24-36) 4 12 7 48 400 14 2640 29040 29,040

15. Julia clears 9 ½ ft in the pole vault. Maya clears 112 in. Which one clears the greatest height? 6 114 inches > Julia jumped higher.

16. Estimation: Matching……. 31.height of a 7-year old 32.weight of a bag of apples 33.width of your palm 34.amount of water in a vase 35.weight of a peach 36.amount of juice in a child’s cup 4 ft. C 4 lb. B 4 in. F 4 c D 4 oz E 4 fl oz A A.4 fl. Oz. B.4 lb C.4 ft. D.4 cups E.4 oz. F.4 inches

17. What did we accomplish? We converted between customary measures We tried to use a new tool, a conversion factor, in dimensional analysis Example of unit conversion….. To find how many centimeters in 2 miles……... If you changed your mind and wanted this distance in meters?????