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

The Metric System

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

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

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.

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 0.000001 Symbol: d c m mc or μ This one is on the DNU list

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.

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 189-190 – practice 1-2: Even Group Work – page 189-190 – practice 1-2: odd Root Use Symbol gram weight g meter length m liter volume L or l

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 192-195 – practice 3-5: Even Group Work – page 192-195 – practice 3-5: odd

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 196-197 – practice 6: Even Group Work – page 196-197 – practice 6: odd 263 grams of dental stone powder 80 milliliters of room temp water