Metric and Household Measurements Chapter 6 Metric and Household Measurements Copyright © 2016 by Elsevier, Inc. All rights reserved. Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Metric System The metric system is the most common and the only standardized system © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Metric Prefixes Micro = one millionth or 0.000001 or of the base unit Milli = one thousandth or 0.001 or of the base unit Centi = one hundredth or 0.01 or of the base unit © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Metric Prefixes (Continued) Deci = one tenth or 0.1 or of the base unit Kilo = one thousand or 1,000 times the base unit © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

International System (SI) of Metric Units and Abbreviations Weight Gram (base unit) – g Milligram – mg Microgram – mcg (µg) Kilogram – kg © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

International System (SI) of Metric Units and Abbreviations (Continued) Volume Liter (base unit) – L (ℓ) Milliliter – mL (mℓ) Cubic centimeter – cc © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

International System (SI) of Metric Units and Abbreviations (Continued) Length Meter (base unit) – m Centimeter – cm Millimeter – mm © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Comparing Common Metric Units PREFIX Kilo- Hecto- Deca- BASE Deci- Centi- Milli- Decimilli- Centimilli- Micro- Weight kilogram gram milligram microgram Volume liter deciliter milliliter Length meter centimeter millimeter Value to Base 1,000 100 10 1.0 0.1 0.01 0.001 0.0001 0.00001 0.000001 © Cengage Learning 2013 © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Remembering Order GRAM LITER METER kilo hecto deca BASE deci centi milli K H D C M “King Henry Died from a Disease Called Mumps” © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

k h d (BASE) d c m BASE is meter, liter, or gram BASE is the only letter that can stand alone To convert metric to metric, use the supplied chart © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

k h d (BASE) d c m (Continued) To convert 1 gram to centigram, you move the decimal as you would in the chart k h d Base d c m So 1 gram = 1.00 = 100 centigrams © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Rules of Metric Notation Unit or abbreviation always follows amount 5 g NOT g 5 Decimals used to designate fractional metric units 1.5 mL, NOT mL © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Rules of Metric Notation (Continued) Use a zero to emphasize decimal point for fractional metric units less than 1 0.5 mg, NOT .5 mg Will prevent potential dosage error If 5 mg was misinterpreted for 0.5 mg, the dosage would be 10 times too much and could be lethal © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Rules of Metric Notation (Continued) Omit unnecessary zeros 1.5 g, NOT 1.50 g This is a critical rule When in doubt, double-check Ask writer for clarification © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Metric Measurements and Equivalents Weight Unit Abbreviation Equivalents gram g 1 g = 1,000 mg milligram mg 1 mg = 1,000 mcg = 0.001 g microgram mcg 1 mcg = 0.001 mg = 0.000001 g kilogram kg 1 kg = 1,000 g k h d Base d c m Check these by using this chart © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Metric Measurements and Equivalents (Continued) Length Unit Abbreviation Equivalents meter m 1 m = 100 cm = 1,000 mm centimeter cm 1 cm = 0.01 m = 10 mm millimeter mm 1 mm = 0.001m = 0.1 cm k h dk Base d c m © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Metric Measurements and Equivalents (Continued) Volume Unit Abbreviation Equivalents liter L (or ℓ) 1 L = 1,000 mL milliliter mL (or mℓ) 1 mL = 0.001 L = 1 cc cubic centimeter cc 1 cc = 1 mL = 0.001 L k h dk L d c m cc Again, this chart really helps © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Unsafe Abbreviations Many health organizations have prohibited the use of “cc” as it has been confused with zeros and units Micrograms should always be abbreviated “mcg” not “µg” The word “unit” must be spelled out; it cannot be abbreviated “U” Review CAUTION blocks in your book for more information © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Units Standardized amount needed to produce a desired effect Used to measure unit of potency Vitamins Chemicals © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Milliequivalents (mEq) One thousandth of an equivalent weight of a chemical Used when referring to serum electrolytes © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Household System of Measurement Unit Abbreviation Equivalents drop gtt teaspoon t (or tsp) tablespoon T (or tbs) 1 T = 3 t ounce (fluid) fl oz 2 T = 1 oz ounce (weight) oz 1 lb = 16 oz cup 1 cup = 8 oz pint pt 1 pt = 2 cups quart qt 1 qt = 4 cups = 2 pt © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Approximate Equivalents 1 t = 5 mL 1 T = 3 t = 15 mL = ½ fl oz 1 fl oz = 30 mL = 6 t 1 L = 1 qt = 32 fl oz = 4 cups 1 pt = 16 fl oz = 2 cups 1 cup = 8 fl oz = 240 mL 1 kg = 2.2 lb 1 in = 2.5 cm © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Commonly Used Prefixes micro = one millionth milli = one thousandth centi = one hundredth kilo = one thousand Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Metric Conversions: Dimensional Analysis Method Set up the single equation by putting the desired answer (which unit of measurement) on the left side. Place the equivalents between the two items in the problem or known factor on the right side. Finally, place the given quantity and the units in which it is supplied also on the right side of the equation. Dimensional analysis has been around for many years. It was first used in the sciences and has now become popular for calculating drug dosages. The advantage of dimensional analysis is that only one equation is needed. Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Metric Conversions: Dimensional Analysis Method Three items are needed to set up the single equation: The desired answer, which goes on the left of the equation The equivalent between the two units in the problem The given quantity and the unit in which it is supplies Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Metric Conversions: Proportion Method Place the equivalent between the two measures (units) on the left side of the proportion. Set up the right side of the proportion so the abbreviations (units) match the left side. Use the symbol x to represent the unknown quantity. Rewrite the proportion without using the abbreviations. Solve for x by multiplying the means and extremes. Write the answer as a decimal. The equivalent measure between two metric measures (units) can be found in Box 6-1. For example, the equivalent measure between grams and milligrams is listed as 1,000 milligrams (mg) in 1 gram (g). Once you have rewritten the proportion without the abbreviations, it becomes a regular proportion equation like you learned how to solve for in chapter 5. Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Conversions: Dimensional Analysis Method For example: 2 ½ cups equals how many milliliters? On the left side of the equation, place the name or abbreviation of the drug form of x, or what you are solving for. X mL On the right side, place the available information related to the measurement that was placed on the left side. This information is placed as a common fraction, with the measurement that matches the x quantity in the numerator. We also know that there are 240 mL in 1 cup. This information is the denominator of our fraction. x mL = 240 mL 1 cup Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Conversions: Dimensional Analysis Method Next, find the information that matches the measurement used in the denominator of the fraction you created. In this example, cup is the denominator and we have 2 ½ cups. Therefore the full equation is: x mL = 240 mL × 2.5 cups 1 cup 1 Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Conversions: Dimensional Analysis Method Now cancel out the like abbreviations on the right side of the equation. If you have set up the problem correctly, the remaining measurements or abbreviation should match that used on the left side of the equation. You are now ready to solve for x. x mL = 240 mL × 2.5 cups 1 cup 1 x = 240 × 2.5 × 600 1 × 1 1   X = 600 mL Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Conversions: Proportion Method Place the equivalent between the two measures (units) on the left side of the proportion. Set up the right side of the proportion so the abbreviations (units) match the left side. Use the symbol x to represent the unknown quantity. Rewrite the proportion without using the abbreviations. Solve for x by multiplying the means and extremes. Write the answer as a decimal. The equivalents between metric and household systems can be found in Box 6-2. For example, the equivalent for converting between grams and pounds is listed as 1,000 grams (g) in 2.2 pounds (lb). Once you rewrite the proportion without the abbreviations, it becomes a regular proportion equation like you learned how to solve for in chapter 5. Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Conversions: Proportion Method Label the answer with the proper abbreviation (unit). For example: 10.2 inches equals how many meters? Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Base Units of the Metric System of Measurement Weight (grams) Volume (liters) Length (meters) What is a unit? A unit is a quantity adopted as a standard of measurement (inches, feet, pounds, and so on). What are some other measurements for which units are used? For examples: Power is measured in watts (100-watt lightbulb, and so on) and horsepower (car engines, and so on); time is measured in seconds, minutes, hours, and years; sound levels are measured in decibels; and temperature is measured in degrees Celsius and degrees Fahrenheit. Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Commonly Used Prefixes micro = one millionth milli = one thousandth centi = one hundredth kilo = one thousand Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Metric Conversions: Dimensional Analysis Method Set up the single equation by putting the desired answer (which unit of measurement) on the left side. Place the equivalents between the two items in the problem or known factor on the right side. Finally, place the given quantity and the units in which it is supplied also on the right side of the equation. Dimensional analysis has been around for many years. It was first used in the sciences and has now become popular for calculating drug dosages. The advantage of dimensional analysis is that only one equation is needed. Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Metric Conversions: Dimensional Analysis Method Three items are needed to set up the single equation: The desired answer, which goes on the left of the equation The equivalent between the two units in the problem The given quantity and the unit in which it is supplies Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Metric Conversions: Proportion Method Place the equivalent between the two measures (units) on the left side of the proportion. Set up the right side of the proportion so the abbreviations (units) match the left side. Use the symbol x to represent the unknown quantity. Rewrite the proportion without using the abbreviations. Solve for x by multiplying the means and extremes. Write the answer as a decimal. The equivalent measure between two metric measures (units) can be found in Box 6-1. For example, the equivalent measure between grams and milligrams is listed as 1,000 milligrams (mg) in 1 gram (g). Once you have rewritten the proportion without the abbreviations, it becomes a regular proportion equation like you learned how to solve for in chapter 5. Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Measurements Weight (pounds) Volume (cups, teaspoons) Length (feet, inches) Why aren’t household units used as the standard in calculating drug dosages? Some reasons include the convenience and ease of using decimals rather than fractions in calculations, the simplicity of naming units (standard prefixes for each base unit), and the accuracy of metric units (the size of a cup varies from institution to institution). Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Conversions: Dimensional Analysis Method For example: 2 ½ cups equals how many milliliters? On the left side of the equation, place the name or abbreviation of the drug form of x, or what you are solving for. X mL On the right side, place the available information related to the measurement that was placed on the left side. This information is placed as a common fraction, with the measurement that matches the x quantity in the numerator. We also know that there are 240 mL in 1 cup. This information is the denominator of our fraction. x mL = 240 mL 1 cup Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Conversions: Dimensional Analysis Method Next, find the information that matches the measurement used in the denominator of the fraction you created. In this example, cup is the denominator and we have 2 ½ cups. Therefore the full equation is: x mL = 240 mL × 2.5 cups 1 cup 1 Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Conversions: Dimensional Analysis Method Now cancel out the like abbreviations on the right side of the equation. If you have set up the problem correctly, the remaining measurements or abbreviation should match that used on the left side of the equation. You are now ready to solve for x. x mL = 240 mL × 2.5 cups 1 cup 1 x = 240 × 2.5 × 600 1 × 1 1   X = 600 mL Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Conversions: Proportion Method Place the equivalent between the two measures (units) on the left side of the proportion. Set up the right side of the proportion so the abbreviations (units) match the left side. Use the symbol x to represent the unknown quantity. Rewrite the proportion without using the abbreviations. Solve for x by multiplying the means and extremes. Write the answer as a decimal. The equivalents between metric and household systems can be found in Box 6-2. For example, the equivalent for converting between grams and pounds is listed as 1,000 grams (g) in 2.2 pounds (lb). Once you rewrite the proportion without the abbreviations, it becomes a regular proportion equation like you learned how to solve for in chapter 5. Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Household Conversions: Proportion Method Label the answer with the proper abbreviation (unit). For example: 10.2 inches equals how many meters? Copyright © 2020 by Mosby, an imprint of Elsevier Inc. All rights reserved.