Chapter 8 Objectives v Name the units in

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

The Metric System

Page 186 The Metric System v 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

Page 187 The Metric System (Cont’d) v 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 weight an item's weight, an amount of medicine length height, length, instruments Gram (g or G) Meter (m)

Page 188 The Metric System (Cont’d) v 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. v Metric conversion problems can be solved by moving the decimal either to the left or to the right.

Page 188 The Metric System (Cont’d) Unit: Value: kilo 1, 000 hecto 100 decka 10 Symbol: k h da base 1 meter (m)/ gram (g)/ liter (L) This one is often gm in medicine Unit: Value: Symbol: deci 0. 1 d centi 0. 01 c milli 0. 001 m micro 0. 000001 mc or μ This one is on the DNU list

Page 188 Using the Metric Symbols v 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 abbreviation for the root word meter, which is m, to form mm. v 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 gram is the root and means weight. The prefixes are the key to deciphering what number of units you have.

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 Root Use Symbol gram weight g meter length m liter volume L or l

Page 190 Changing Unit Measures v To change units within the metric system, count the spaces from the number you are starting with to the unit you are converting to.

Pages 195 – 196 Using Proportions and Metric Units to Measure Dental Stone v 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. 263 grams of dental stone powder 80 milliliters of room temp water