Dimensional Analysis A scary sounding name for something that is pretty darn easy. Why it’s important to include your UNITS • Units are essential to understanding data. • A unit gives definition to a numerical value. • 100 = number. 100 what? – The number alone does not tell us much. • 100 kg is a quantity. – The unit gives us more information. Scientists speak METRIC! - When scientists measure anything they use the metric system. - 3 basic units are: • Mass = Gram • Volume = Liter or m3 • Length = Meter Just add a PREFIX (Language Arts in Science, Crazy!!) The basic units can be further defined by adding a prefix. The main units we will use are: • Kilo = 1000 • Centi = 1/100 • Milli = 1/1000 Tools for Measure • Mass= Scale • Volume= • Meter stick • Ruler • Graduated cylinder (displacement) • Length= • Meter stick • Ruler Converting Units Dimensional Analysis a.k.a. Factor Labeling • We use proportions to convert from one unit to another. • Some rules to remember: – Carry your units through the entire problem. Don’t lose them. – Use what you know or info that you are given (pg. 6- “Tools of a Scientist” binder packet). Example Problem: How many centimeters in 2 meters? • We know how many meters. We want to know how many centimeters that is. • Known fact: 1 m = 100 cm • Turn what you know into a ratio 2m X 100cm 1m = 200cm Let’s Practice. Work with a partner, then check with your table 1. 2. 3. 4. 5. 6. How many grams in 5 kg? How many centimeters in 6km? How many millimeters in 1.5cm? How many milliliters in 2.3 L? How many meters in 16.4 km? How many liters is 460 ml?