1. Objectives Chapter 8 Name the units in the metric system
Convert metric units to standard units
Complete metric-to-metric conversions
Use ratio and proportion to make dental stone measurements
Identify how the metric system is used in the health care field

2. The Metric System

3. Page 186
The Metric System
Metric measurements are used for many types of measurements in the healthcare professions. Some uses include the following:
Weight calculations
Dosage calculations
Food intake (in grams) measurements
Height and length measurements
Liquid and medication measurements

4. The Metric System (Cont’d)
Page 187
The Metric System (Cont’d)
Metric units come in base units. These units measure different types of materials.
Basic Unit
Measurement type
Examples
Liter (l or L)
volume
liquids, blood, urine
Gram (g or G)
weight
an item's weight, an amount of medicine
Meter (m)
length
height, length, instruments

5. The Metric System (Cont’d)
Page 188
The Metric System (Cont’d)
The metric system use unit based on multiples of ten. For this reason metric numbers are written in whole numbers or decimal numbers, never fractions.
Metric conversion problems can be solved by moving the decimal either to the left or to the right.

6. The Metric System (Cont’d)
Page 188
The Metric System (Cont’d)
Unit:
kilo
hecto
decka
base
Value:
1,000
100 10 1
Symbol: k h da
meter (m)/ gram (g)/ liter (L)
This one is often gm in medicine
Unit:
deci
centi
milli
micro
Value:
0.1
0.01
0.001
Symbol: d c m
mc or μ
This one is on the DNU list

7. Using the Metric Symbols
Page 188
Using the Metric Symbols
The metric system, a unit of measure (a prefix) and a base element (a root word) form the metric units. To form abbreviation for millimeter, use the first letter of the prefix milli, which is m and add it the the abbreviation for the root word meter, which is m, to form mm.
Together, the prefix and root indicate the type of measurement, as in volume, weight, or length. For example, in the word “kilogram,” kilo- is the prefix and means thousand and gram is the root and means weight. The prefixes are the key to deciphering what number of units you have.

8. Using the Metric Symbols (cont’d)
Pages 188 – 189
Using the Metric Symbols (cont’d)
Prefix
Meaning
Symbol
kilo
thousand k
hecto
hundred h
decka
ten da
base
one
m, g, L
deci
tenth d
centi
hundredth c
milli
thousandth m
micro
millionth mc
Examples – page – practice 1-2: Even
Group Work – page – practice 1-2: odd
Root
Use
Symbol
gram
weight g
meter
length m
liter
volume
L or l

9. Changing Unit Measures
Page 190
Changing Unit Measures
To change units within the metric system, count the spaces from the number you are starting with to the unit you are converting to.
Example – page – practice 3-5: Even
Group Work – page – practice 3-5: odd

10. Using Proportions and Metric Units to Measure Dental Stone
Pages 195 – 196
Using Proportions and Metric Units to Measure Dental Stone
Dental assistants need to mix dental stone material for dental molds making a uniform and consistent material for the mold. The amount of stone and water varies according to the size of the mold needed. This task uses the metric system: Dental stone is measured by weight in grams, and room temperature water is measured by volume in milliliters. Knowledge of the metric system coupled with the use of ratio and proportion help maintain the correct ratio of dental stone to water.
Example – page – practice 6: Even
Group Work – page – practice 6: odd
263 grams of dental stone powder
80 milliliters of room temp water