Dimensional
Analysis for Meds
Chapter 4
Chapter 4

Metric, International (SI) System
 You
do not need to know all of the System!
 Much easier than English System
 All units of measure differ from teach other in
powers of ten (10).
 Conversions between units in the system are
accomplished by simply moving the decimal
point.
English Lengths
12 inches = 1 foot
 3 feet = 1 yard
 5 ½ yards = 1 rod
 40 rods = 1 furlong
 8 furlongs = 1 mile

English Weights
27 11/32 grains = 1 dram
 16 drams = 1 ounce
 16 ounces = 1 pound
 200 pounds = 1 ton

English Volumes
2 pints = 1 quart
 4 quarts = 1 gallon
 31 ½ gallows = 1 barrel
 2 barrels = 1 hogshead

English Lengths

12 inches = 1 foot
3 feet = 1 yard
5 ½ yards = 1 rod
40 rods = 1 furlong
8 furlongs = 1 mile

500 inches x 1 foot/12 inches = 41.67 feet

500 in x 1 ft/12 in x 1 yrd/3 ft = 13.89 yards





If you have a piece of sting
that is 500 inches long, how
many feet is that? How many
yards?
Metric System

3 Basic words
 Meter
= length
 Gram = weight
 Liter = volume

It does not mater what prefix you have.
Small Group Quiz!
1.
2.
3.
4.
5.
Milligram
Centimeter
Milliliter
Kilometer
Microgram
L = Length
W = Weight
V = Volume
Small Group Quiz!
1.
2.
3.
4.
5.
Milligram = (W) weight
Centimeter = (L) length
Milliliter = (V) volume
Kilometer = (L) length
Microgram = (W) weight
Metric prefixes

Same prefix for length, volume, weight.
 Kilogram
 Kiloliter
 Kilometer
Kilo

Kilo
 Prefix
 Larger
than basic by 1000
1 kilometer = 1000 meters
 1 kilogram = 1000 grams
 1 kiloliter = 1000 liters

3 Prefixes (smaller than basic)
Centi – ( centimeter) 100x smaller than basic
 Milli – (Millimeter) 1000x smaller than basic
 Micro (microgram) 1,000,000x smaller than basic


1 Kilometer =
 1000

1 meter =
 1000

meters
millimeters
1 millimeter =
 1000
micrometer

1 Kilogram =
 1000

1 gram =
 1000

gram
milligram
1 milligram =
 1000
microgram

Kiloliter =
 1000

1 Liter =
 1000

Liter
milliliter
1 milliliter =
 1000
microliter
Symbols

Basic unit
 Meter
=m
 Liter = L
 Gram = g

Prefix
Kilo = k

Kiloliter = kL
Centi

Centimeter = cm
Milli

=m
Millimeter = mm
Micro

=c
= mc
Microgram – mcg
Rules!
 mL
= cc
Do
not chart
 Microgram
Do
= mg
not chart
Small group Quiz

1.
2.
3.
4.
5.
6.
Write the following in abbreviated form
Microgram
Milliliter
Kilometer
Kilogram
Microliter
Centimeter
Small group Quiz

1.
2.
3.
4.
5.
6.
Write the following in abbreviated form
Microgram = mcg
Milliliter = mL
Kilometer = km
Kilogram = kg
Microliter = mcL
Centimeter = cm
Metric System & Meds

Only use dosages that differ by 1000 units to the
next measurement
Weight
1 kg = 1000 g
1 g = 1000 mg
1 mg = 1000 mcg
Volume
1 L = 1000 mL
Conversions between units
Conversion between units are
accomplished by moving the decimal
point!
 How far? (How many places)?

 How

many “0” in 1000?
3
 Move
the decimal point 3 places
Conversions between units

Which direction do you move the decimal point?
 IF large units to small units
The quantity (number) must get larger
 Large  smaller
 Move the decimal to the right

 0.5

g = __?__ mg
g to mg is a difference of 1000 units

Kg g  mg  mcg
Large  smaller
 500 mg

Conversions between Units
 2.5

L = __?__ mL
L to mL is a difference of 1000 units



Large  small
2500 mL
 500

mg = __?__ mcg
mg to mcg is a difference of 1000 units



L  mL
Kg  g  mg  mcg
Large  small
500,000 mcg
Small Group Practice
1.
2.
3.
4.
5.
9 mg = ___?___ mcg
2.3 L = ___?___ mL
0.09 kg = ___?___ g
4.7 g = ___?___ mg
0.75 kg = ___?___ g
Small Group Practice
1.
2.
3.
4.
5.
9 mg = 9000 mcg
2.3 L = 2300 mL
0.09 kg = 90 g
4.7 g = 4700 mg
0.75 kg = 750 g
Conversions between Units


What if we are converting up the scale, going
from smaller  larger units?
Move the decimal point 3 places to the Left
 200

mL = ___?___ L
mL to L is different of 1000 units



L  mL
Smaller  larger
0.2 L
Conversions between Units
 50

mcg = ___?___ mg
mcg to mg is different of 1000 units

Kg  g  mg  mcg
Smaller  larger
 0.05 mg

Small group Practice
1.
2.
3.
4.
5.
4200 mL = ___?___ L
520 mg = ___?___ g
30 mcg = ___?___ mg
7420 g = ___?___kg
2.2 L = ___?___ mL
Small group Practice
1.
2.
3.
4.
5.
4200 mL = 4.2 L
520 mg = 0.52 g
30 mcg = 0.03 mg
7420 g = 7.42 kg
2.2 L = 2200 mL