1. Medical Dosage Calculations A Dimensional Analysis Approach
Eleventh Edition
Chapter 3
Dimensional Analysis

2. Learning Objectives (1 of 2)
3.1 Identify some common units of measurement and their abbreviations. 3.2 Construct unit fractions from equivalences. 3.3 Convert a quantity expressed with a single unit of measurement to an equivalent quantity with another single unit of measurement. 3.4 Solve, using Dimensional Analysis, both simple (one-step) and complex (multi-step) problems involving single units of measurement.
Slide 2 is list of textbook LO numbers and statements

3. Learning Objectives (2 of 2)
3.5 Convert a quantity expressed as a rate to another rate. 3.6 Solve, using Dimensional Analysis, both simple (one- step) and complex (multi-step) problems involving rates.
Slide 3 is list of textbook LO numbers and statements

4. Dimensional Analysis
Dimensional Analysis is a method used in sciences like physics and chemistry.
We are analyzing dimensions
It is also referred to as the “conversion factor method.”
Concept 1: When a nonzero quantity is divided by the same amount, the result is 1.
Concept 2: When a quantity is multiplied by 1, the quantity is “unchanged”

5. Units of Measurement (1 of 3)
UNITS OF MEASUREMENT are also referred to as:
Units of Measure
Labels
Dimensions
Units

6. Units of Measurement (2 of 3)
Examples:
inches
feet
days
minutes
hours

7. Units of Measurement (3 of 3)
Table 3.1 Equivalents for Some Common Units of Measurement
12 inches (in) =
1 foot (ft)
2 pints (pt)
1 quart (qt)
16 ounces (oz)
1 pound (lb)
60 seconds (sec)
1 minute (min)
60 minutes (min)
1 hour (h or hr)
24 hours (h or hr)
1 day (d)
7 days (d)
1 week (wk)
12 months (mon)
1 year (yr)

8. Changing Single Units of Measurement
Changing a Single Unit of Measurement to another Single Unit of Measurement in One Step Suppose that you want to change 3 years into an equivalent number of months. The relationship is written as follows: 3 yr = ? mon

9. Unit Fraction (1 of 2)
A fraction equal to 1 is called a unit fraction.
Since 12 months is equivalent to 1 year, then dividing 12 months by 1 year results in 1.

10. Unit Fraction (2 of 2)
When a quantity is multiplied by 1, the quantity is unchanged.

11. Changing Units of Measurement (1 of 2)
Changing a Single Unit of Measurement to another Single Unit of Measurement in Multi-Steps Suppose that you want to change 2 days into an equivalent number of minutes. The relationship is written as follows: 2 d = ? min

12. Changing Units of Measurement (2 of 2)
2,880

13. Changing Rates (1 of 4)
Changing a Rate to another Rate in One Step Suppose that you want to change 3 oz per day into an equivalent rate in oz per week The relationship is written as follows:

14. Changing Rates (2 of 4)
Use the equivalence 1 wk = 7 d

15. Changing Rates (3 of 4)
Changing a Rate to another Rate in Multi-Steps Suppose that you want to change 8 oz per day into an equivalent rate in lb per week The relationship is written as follows:

16. Changing Rates (4 of 4)
Using equivalencies 1 wk = 7 d and 1 lb = 16 oz
= 3.5