1. MEASUREMENT SYSTEMS & SCIENTIFIC NOTATION
MODULE A - 4
MEASUREMENT SYSTEMS & SCIENTIFIC NOTATION

2. OBJECTIVES At the end of this module, the student will be able to…
Identify and compare the systems of measurement used in the clinical setting.
Identify the standard prefixes used in the metric system
State the metric units of length, mass, volume, time, and temperature.
Distinguish between the metric units for liquid (mL) and solid volume (cc) measurements.

3. Measurement systems Method of quantifying matter
Solids, liquids & gases
Quantities include:
Length
Area
Weight
Volume
Pressure
Temperature
Time
Systems used in medicine:
A. Conventional
B. Metric
C. Standard International

4. Conventional Systems Also known as: Commonly used in U.S. FPS British
English
U.S Customary
(FPS) foot, pound, second
Commonly used in U.S.
FPS

5. Examples of length & area
12 inches = 1 foot
3 feet (36 inches) = 1 yard
220 yards = 1 furlong
8 furlongs = 1 mile
1,760 yards = 1 mile
5,280 feet = 1 mile
1 sq. foot (foot2) = 122 sq. inches
1 sq. yard (yard2) = 9 sq. feet
43,560 sq. feet = 1 acre
1 sq. mile (mile2) = 640 acres

6. Examples of liquid measure
1 teaspoon (tsp) = 1/3 tablespoon
2 tablespoon (tbsp) = 1 fluid ounce
1 fluid ounce (oz) = 1/8 cup
2 fluid ounces = 1/4 cup
2 2/3 fluid ounces = 1/3 cup
4 fluid ounces = 1/2 cup
5 1/3 fluid ounces = 2/3 cup
6 fluid ounces = 3/4 cup
8 fluid ounces = 1 cup
2 cups (c) = 1 pint
2 liquid pints (pt) = 1 liquid quart (qt)
4 liquid pints = 1 gallon (gal)

7. Examples of dry measure
1 dry quart = 2 dry pints
8 dry pints = 1 peck
4 pecks = 1 bushel

8. Standard International (SI)
Simplified modification of metric system.
Worldwide effort started in 1960s to standardize to this system.
Also known as:
(MKS) meter, kilogram, second
MKS

9. Standard International Units
Comparison
Conventional Units
Standard International Units
Length
inch or foot
meter
Volume
Fluid ounce
Cubic Foot (ft3)
Liter
Area
in2 or ft2 m2

10. Metric System Developed in Europe.
Has all units based on multiples of 10.
Also known as:
(CGS) centimeter, gram, second
CGS

11. Measurements in Respiratory Therapy
Length
Meter (m)
Volume
Liter (L)
Mass
Gram (g)
Time
Seconds (sec)
Temperature
Centigrade (Celsius), Kelvin, Fahrenheit
Pressure
Centimeters of Water (cm H2O), Pounds per square inch (psi), Millimeters of mercury (mm Hg), Torr, Pascal (Pa), and Atmospheres (atm)
Force
Dynes

12. Conversion Conversion within the metric system is easy
Everything based on multiples of ten.
Conversion from one system to the other:
Must know the conversion factors.

13. Conversion
Conversion within these systems or from one system to the other:
You Must know how to do metric conversions.
I will provide the S.I. and conventional factors on an exam or quiz.
There are too many to memorize.
Gimli Glider & Mars Climate Orbiter

14. Basic (fundamental) Units
Basic unit has value of one. (1x100 = 1)
One Liter
Smaller - milliliter
Larger - kiloliter
One Gram
Smaller – microgram
Larger - hectogram
One Meter
Smaller - decimeter
Larger - Megameter
Larger
Smaller
Opposite of the number line

15. Basic or Fundamental Unit
Metric Chart
Basic or Fundamental Unit
Liter
Gram
Meter
| | | | | | | | |------| |
kilo hecto deca deci centi milli
x x100 x10
(k) (h) (da) (d) (c) (m)
LARGER SMALLER

16. Greek Prefixes - Units to the left of the basic unit and larger.
BASIC UNIT = One Liter, Gram or Meter
deca (da) 10 x larger 10
hecto (h) 100 x larger 100
kilo (k) x larger 1000
10 4
10 5
Mega (M) 1,000,000x 1,000,000
10 7
10 8
Giga (G) 1,000,000,000x 1,000,000,000

17. Latin Prefixes Units to the right of the basic unit and smaller.
BASIC UNIT = One Liter, Gram or Meter
deci (d); 10 x smaller; 1/10; x 0.1
centi (c); 100 x smaller; 1/100; x 0.01
milli (m); 1000 x smaller; 1/1,000; x 0.001
10 -4
10 -5
micro (m) or (mc); 1,000,000 x smaller; 1/1,000,000; x
10 -7
10 -8
nano (n); 1,000,000,000 x smaller; 1/1,000,000,000; x
10-10 Angstrom (Å); 10,000,000,000 x smaller; 1/10,000,000,000; x

18. Scientific Notation
A method of expressing the value of a very small or very large number.
Scientific Notation: (base exponent)
Base is the number to be multiplied by itself (usually 10).
Exponent is the number of times it is multiplied.
103 = 10 x 10 x 10 = 1,000

19. Scientific Notation Example:
A kilometer is 1,000 times larger than a meter
Count the zeros (that equals exponent)
103
10x10x10 times larger

20. Scientific Notation Example:
Angstrom (Å) is 10 billion times smaller than a meter (m)
That is…10,000,000,000 times smaller
Count the zeros to determine exponent
or or
Can also be written as
10x10x10x10x10x10x10x10x10x10 times smaller

21. Numbers and Exponents 100 = 1 a x 100 = a 101 = 10 a x 101 = a x 10

22. Numbers and Exponents Positive exponent = # of zeros 5 x 100 = 5
Negative exponent = # of decimal places
5 x =
5 x =
5 x =
5 x =
5 x =

23. Examples - Avogadro’s Number
Expresses the number of atoms in one mole of a gas
Long form:
602,000,000,000,000,000,000,000 atoms
Scientific notation:
6.02 x atoms
Process: Count over to the left, the number of decimal places to get a number between 1 & 10

24. Example - Mass of an electron
Long Form:
grams
Scientific Notation:
9.11 x grams
Process: Count over to the right the number of decimal places necessary to get a number between 1 and 10

25. Practice: Express the following exponentially
(count over to left 2 decimal places)
93,000,000 = _________________
= _________________
= _________________

26. Exponent Relationship to Basic Unit
Negative exponents are smaller (10 –3)
Positive exponents are larger (10 3)
If the metric system was money…
| | | | | |
$1, $ $ $ cent 1cent
Basic Unit
0.10
0.01

27. One more point regarding units of measure.

28. Why is mL and cc (cm3) the same?
Cubic centimeter (cc or cm3) and millimeter (mL) are used interchangeably in medicine.
The unit cc is a length measurement.
The unit mL is a volume measure.
A cube 1 cm long x 1 cm wide by 1 cm high (l x w x h = area) will hold 1 mL of liquid volume.
We therefore use the units interchangeably.
1 cc or cm3 = 1 mL

29. The volume of this cube
is one mL.
1 cm deep
1 cm high
Cubic centimeter
1 mL = 1 cc = 1 cm3
1 cm length

30. Additional Conversion Factors
Length:
1 meter = inches
1 cm = inches
1 km = 0.62 miles
Volume:
1 mL = 1 cc = 1 cm3
1 L = qts.
946 mL = 1 qt.
1 pint = 473 mL
1 kg = 2.2 pounds (lbs)
1 lb = 454 grams