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5.1 Introduction, Base Units, and Prefixes
• Metric system base units:
(L)liter volume
(cd) candela intensity luminous
(A) ampere current electrical
(mol) molesubstanceofamount
C)( Celsius degreesetemperatur
(s) secondtime
(kg) kilogramt)mass(weigh
(m)meter length
5.1 Introduction, Base Units, and Prefixes
Multiple in decimal form
Power of 10 Prefix Symbol
1000 103 kilo k
100 102 hecto h
10 101 deka da
1 100 base unit
0.1 10-1 deci d
0.01 10-2 centi c
0.001 10-3 milli m
0.000001 10-6 micro
5.1 Introduction, Base Units, and Prefixes
• Charting in the metric systemMain Rule: Amount as a decimal then the metric abbreviation (do not leave a space)
Examples:three-fourths gram = 0.75gfive and a half centimeters = 5.5cmtwenty milligrams = 20mgone-half milliliter = 0.5ml
Note: leave a space for clarity in your computations
5.2 Metric Length
• English lengths and similar metric lengths:
Yard Meter
Inch Centimeter
Mile Kilometer
5.2 Metric Length
• Conversions:
Note: In Canada, speed is in kph instead of mph
mileskm
mileskm
inchesm
inchescm
1.35
621.01
37.391
394.01
5.2 Metric Length
• Chart the following lengths:
– Five-fourths of a centimeter ________
– Seven and a half millimeters ________
5.3 Metric Volume
• Conversions
mlteaspoon
quartsliter
mlcc
cccmliter
51
057.11
11
100010001 3
5.3 Metric Volume
• Try these:
– 3.5 liters = ________ ml
– liter = ________ cc81
5.4 Metric Mass
• 1 gram = weight of 1 ml of water
• Basic unit = 1Kg = 1000 grams
• 1 liter of water weighs 1 Kg
5.4 Metric Mass
• Applications for metric mass:Unit Symbol Use
micrograms g Pharmaceutical measurement
milligrams mg Pharmaceutical measurement
gram g Dietary instructionBody mass of infant
Pharmaceutical measurement
Kilogram kg Body mass (children and adults
Orthopedic traction weight
5.5 Metric Time
• Basic unit = second
• Dates: day month year format or year month day format
5.5 Metric Time• 24-hour clock
midnight
MP
MP
MP
Noon
MA
MA
midnight
00:122400
..59:112359
..30:61830
..01:121201
00:121200
..00:60600
..01:120001
00:120000
5.5 Metric Time
• Examples of dates in correct chronological order:
– Wrong: April 12, 1942Correct: 12 April 1942
– Wrong: 11/1/07Correct: 07 · 11 · 1
5.6 Metric Temperature
• Kelvin is the basic unit, but Celsius is more commonly used as a base unit
boils water 100
raturebody tempe normal 37
re temperaturoom 2220
freezes water 0
273
C
C
C
C
KC
5.6 Metric Temperature
• Clinical thermometer in degrees Celsius
re temperatuabnormal 35
re temperatusubnormal 36
raturebody tempe normal 37
fever grade low 38
feverhigh 39
fever dangerous 41
C
C
C
C
C
C
5.7 Internal Metric Conversions
• Metric Conversion Chart
kilo-, hecto-, deka- meterlitergram
deci-, centi-, milli-
Move the decimal point the same number of places and in the same direction the unit moves on the chart.
5.7 Internal Metric Conversions
• Example: Using the metric conversion chart, change 3500 liters to hl (hectoliters)
– To go from liters to hectoliters on the chart, move the decimal place to the left 2 places
shectoliterliters 00.353500
6.1 Conversion Methods
• Use Appendix B for converting between the apothecaries’ and metric system
• Converting units using a proportion
fraction a as equivalent conversion unitdesired
amountgiven
6.1 Conversion Methods
• Example: Change 400 m to km
kmx
x
km
m
kmx
m
4.01000
400
4001000
1
1000
400
6.1 Conversion Methods
• To convert units using the factor-label method:
Note: sometimes this will require more than one conversion/multiplication
amountdesiredgivenunit
desiredunitamountgiven
6.1 Conversion Methods
• Example: Convert 5 gallons to pints
Notice how the units “cancel”
pints40
1
pints2
1
45
quartgallon
quartsgallons
6.2 Word Problems
• Example: A doctor orders 5 gr. Of medication. The medication is available in 100 mg tablets. How many tablets would you give? If the medication came in 150 mg tablets, how many would you give?
6.2 Word Problems
• Using a proportion:
2525
2
5
1
150
60
.1
.5
3535
3
5
60
.100
1
100
60
.1
.5
xx
tablet
mg
mg
gr
tabletsx
gr
xx
tablet
gr
tablet
mg
mg
gr
tabletsx
gr
6.2 Word Problems
• Using the factor-label method
tabletsmg
tablet
gr
mggr
tabletsmg
tablet
gr
mggr
2150
300
150
1
.1
60.5
3100
300
100
1
.1
60.5
6.3 Temperature Conversion
• •
• C-F Temperature Conversion• F-C Temperature Conversion
3259 CF
)32(95 FC
Supplement 3.1 Direct Variation
• Types of variation:1. y varies directly as x:
2. y varies directly as the nth power of x:
nkxy
kxy
Supplement 3.1 Direct Variation
• Solving a variation problem:1. Write the variation equation.
2. Substitute the initial values and solve for k.
3. Rewrite the variation equation with the value of k from step 2.
4. Solve the problem using this equation.
Supplement 3.2 Inverse Variation
• Types of variation:1. y varies inversely as x:
2. y varies inversely as the nth power of x: nx
ky
x
ky
Supplement 3.2 Inverse Variation• Example: If t varies inversely as s and
t = 3 when s = 5, find s when t = 5
1. Give the equation:
2. Solve for k:
3. Plug in k = 15:
4. When t = 5: 315515
5 sss
s
kt
155
3 kk
st
15
