Units of Measurement Conversion Factors Unit Conversions Units of Measurement Conversion Factors

SI Measurements The international system of measurement The metric system A set of agreed-upon standard units of measurement Numbers are written without commas 1 000.00 not 1,000.00 Some countries use commas to represent a decimal point.

SI Units Prefixes are added to base units to represent larger or smaller quantities and measurements Base Units: Mass = grams (g) Volume = Liters (L) or cubic meters (m3) Length = meters (m) Time = second (s) Temperature = Kelvin (K) Amount of a substance = moles (n) (1 mL = 1 cm3)

Conversion factors A ratio (fraction) that shows the equality of two different units. Used to convert from one unit to another Written as FRACTIONS Can be written upside down too! Dimensional Analysis = a math technique for solving problems that involve measurements

Example 4 quarters = 1 OR 1 dollar = 1 1 dollar 4 quarters We know that 4 quarters = 1 dollar Conversion factors: 4 quarters = 1 OR 1 dollar = 1 1 dollar 4 quarters 1 quarter = 1 OR 0.25 dollar = 1 0.25 dollar 1 quarter If I have 27 quarters, how much money do I have in dollars? 27 quarters x 1 dollar = 27 ÷ 4 = $6.75 4 quarters

Steps for solving problems: 1. Write down the number given to change (the value in the question/problem). 2. Drop the unit that goes with the number to the bottom of the next fraction. 3. Each ratio (or fraction) you multiply is a known quantity (like 4 quarters=1 dollar). 4. Keep multiplying by ratios that you know until you come to the unit you want to end with.

Example 1 Convert 180 miles into feet. Given: 1 mile = 5,280 feet

Example 2 Convert 27 days into seconds. What givens do we know?

Example 3 If prefixes are used, always go back to your base unit and kick off from there. Ex: Convert 22 kilograms into centigrams.

Sample Problems Complete the following and determine what kind of measurement it represents (mass/volume/etc.): 10.5 g = ______ kg 1.57 km = ______ m 3.54 μg = _________ g 1.2 L = _______ mL 932 seconds = ______ minutes 548.6 mL = ______ cm3

Unit Conversions Worksheet For each problem, follow the guidelines: --Keep dropping your unit! --Watch parentheses! --Include units in the answer! --Prefix with base only

Units m=meter min=minutes s=seconds mi=miles gal=gallons g=grams k=kilo--____

Multi-Step Problem 12.4 cm=_____ km 133 mL=_____ gallons 64.33 mi= _____ yards