Metric Measurements

Name: Key Date: TITLE: Metric Measurement Science is based on measurements MEASUREMENTS - All measurements have - Magnitude - Uncertainty - Units Math is based on numbers NUMBERS - Exact numbers are obtained by - Counting - Definitions Also known as the SI System - "SI" stands for "Le Système International d'Unités" - Law in France since 1790. - It is based on the number 10 - Always used in science Base SI Units - Le Système Internationale (SI) units are standard in science QUANTITY BASE UNIT SYMBOL mass kilogram kg length meter m time second s temperature kelvin K Other Base Units: Count/Quantity mole mol Temperature Celsius °C Conversion you need to know: K = °C + 273 DERIVED UNITS - Built from base SI units DERIVED UNIT CALCULATION UNITS AREA length x length m² VELOCITY length/time m/s DENSITY mass/volume kg/m³ VOLUME OF A SOLID length x height x width m³ - Usually derived units are expressed with positive/negative exponents (ex. m²) Can do Under Elmo: Prefixes go in front of the unit Prefixes Symbol Multiply Base Unit by: Example tera T 1,000,000,000,000 teragram (Tg) = 10^12 g giga G 1,000,000,000 gigaliter (GL) = 10^9 L mega M 1,000,000 megagram (Mg) = 10^6 g kilo k 1,000 kilogram (kg) = 10^3 g hecto h 100 hectogram (hg) = 10^2 g deka da 10 decagram (dag) = 10^1 g (unit) (unit) 1 (meter) (m) = 10^0 m deci d 1/10 deciliter (dL) = 10^-1 L centi c 1/100 centimeter (cm) = 10^-2 m milli m 1/1,000 millimeter (mm) = 10^-3 m micro µ 1/1,000,000 microgram (µg) = 10^-6 g nano n 1/1,000,000,000 nanoliter (nL) = 10^-9 L pico p 1/1,000,000,000,000 picogram (pg) = 10^-12 g femto f 1/1,000,000,000,000,000 femtomole (fmol) = 10^-15 mol Metric Conversions by Moving the Decimal King Henry Died Unexpectedly Drinking Chocolate Milk KHDUDCM Steps to move decimal: 1. Start at given prefix 2. Count # of letters (prefix initials) to get to desired prefix 3. Note direction 4. Move decimal same number as letters counted in same direction 5. May need to add zeros to the left or right of original decimal. Practice 0.5 km = 500 m 2,000 cm = 20 m Precision Reproducibility - Check by - Poor precision results from Accuracy - Correctness - Check by - Poor accuracy results from %Error Accuracy is often determined by calculating the %Error the data. If the %Error is less than 5%, the data is considered accurate. 1