Measurement Systems and Conversion Procedures Chapter 3 Measurement Systems and Conversion Procedures

© 2010 Delmar, Cengage Learning. Objectives Interpret the systems of measurement Simplify units using dimensional analysis Perform metric system conversions Perform conversions between metric and nonmetric systems © 2010 Delmar, Cengage Learning.

© 2010 Delmar, Cengage Learning. Objectives (cont’d.) Perform conversions between apothecary and household systems Perform temperature conversions between Celsius, Fahrenheit and Kelvin © 2010 Delmar, Cengage Learning.

Systems of Measurement United States Customary System of Measurement: Distance: 1 ft = 12 in 1 yd = 3 ft 1 mi = 5280 ft Volume: 8 fl oz = 1 cup 1 pt = 2 cups 1 qt = 2 pt 4 qt = 1 gal © 2010 Delmar, Cengage Learning.

Systems of Measurement (cont’d.) Metric system: m → meter → Length l or L → liter → Volume g → gram → Weight 0.91 m = 1 yd 3.79 L = 1 gal 28.3 g = 1 oz © 2010 Delmar, Cengage Learning.

Systems of Measurement (cont’d.) Table 3.1 Metric Prefixes and Values © 2010 Delmar, Cengage Learning.

Basic Dimensional Analysis Algebraically changing or converting units of measure . Grams per liter © 2010 Delmar, Cengage Learning.

Conversions Within the Metric Systems Horizontal format: 1. Identify decimal location in the number being converted 2. Identify prefix location on horizontal diagram 3. Find the difference between the two exponents associated with each prefix © 2010 Delmar, Cengage Learning.

Conversions Within the Metric Systems (cont’d.) Horizontal format: 4. Conversion is moving right on the diagram: Move decimal to the right by the amount calculated in step 3 5. Conversion is moving left on the diagram: Move the decimal to the left by the amount calculated in step 3 Figure 3.1 Horizontal format for metric prefixes and values © 2010 Delmar, Cengage Learning.

Conversions Within the Metric Systems (cont’d.) Horizontal format: (cont’d.) Convert 12 mL to microliters Identify decimal: 12.0 Identify prefixes in diagram Difference is -3 –(-6) = 3 12 mL = 12,000 μL © 2010 Delmar, Cengage Learning.

Conversions Within the Metric Systems (cont’d.) Dimensional analysis: 1 will always be placed with two-letter unit Convert: 12μL to mL . © 2010 Delmar, Cengage Learning.

Conversions Between Metric and Nonmetric Table 3.2 Relationships between the U.S. System and the Metric System © 2010 Delmar, Cengage Learning.

Conversions Between Metric and Nonmetric (cont’d.) Convert 5 kg to oz: Convert kg to lbs Convert lbs to oz © 2010 Delmar, Cengage Learning.

© 2010 Delmar, Cengage Learning. Apothecary Systems Apothecary equivalents: 1 fl oz = 8 fl dr 4 mL = 1 fl dr 60 minims = 1 fl dr 1 g = 15 gr 1 gr = 60 mg 1 mL = 16 minims 1 pt = 16 fl oz 1 qt = 2 pt © 2010 Delmar, Cengage Learning.

Apothecary Systems (cont’d.) 50mg is how many grains? . © 2010 Delmar, Cengage Learning.

Apothecary Systems (cont’d.) 250 fl dr equals how many milliliters? . © 2010 Delmar, Cengage Learning.

© 2010 Delmar, Cengage Learning. Household Systems Household equivalents: 60 drops (gtt) = 1 tsp 1 fl oz = 30 mL 2 tbs = 1 oz 6 fl oz = 1 teacup 8 fl oz = 1 glass 16 oz = 1 lb 1 cup = 8 fl oz 5 mL = 1 tsp © 2010 Delmar, Cengage Learning.

Household Systems (cont’d.) You drank 3 ½ glasses of water How many ounces did you consume? . © 2010 Delmar, Cengage Learning.

Household Systems (cont’d.) How many tablespoons are in 12oz? . © 2010 Delmar, Cengage Learning.

Household, Apothecary, and Metric Equivalents © 2010 Delmar, Cengage Learning.

Temperature Conversions Three scales to measure temperature: Fahrenheit Celsius Kelvin Converting Celsius to Fahrenheit: . or © 2010 Delmar, Cengage Learning.

Temperature Conversions (cont’d.) 0°C equals how many °F? °F = (0° × 1.8) + 32°= 0° + 32° = 32° 75°F equals how many °C? . © 2010 Delmar, Cengage Learning.

Temperature Conversions (cont’d.) Converting Celsius to Kelvin: K = °C + 273.15 100°C K = 100° + 273.15° = 373.15° Converting Kelvin to Fahrenheit: °F = 1.8K − 459.67° 300K °F = 1.8(300°) − 459.67° = 80.33° © 2010 Delmar, Cengage Learning.

© 2010 Delmar, Cengage Learning. Summary To perform metric conversions, we must be familiar with Table 3.1 Conversions within the metric system can be done using the horizontal format Apothecary system: used in calculating drug dosages Household system: used when administering medications in the home © 2010 Delmar, Cengage Learning.

© 2010 Delmar, Cengage Learning. Summary (cont’d.) The three main temperature formulas: © 2010 Delmar, Cengage Learning.