1. Unit 1: Data Analysis Units of Measurements

2. Measurement is a part of daily activities Examples?

3. Why would scientists want a common system of measurement? Scientists need to report data in such a way that it can be understood and reproduced by other scientists across the world 1999 Mars Orbiter (NASA lost $125 million) –mistake was made because one engineering team used metric units while another used English units

4. English Units QuantityEnglish Units length/distance inches (in), feet (ft), yards (yd), miles (mi) mass ounces (oz), pounds (lb), tons (t) volume fluid ounce (oz), cup (c), pints (pt), liters (l), quarts (qt), gallons (gal)

5. Systéme International d'Unités (1960) abbreviated SI units The other name for the metric system This system is used by scientist worldwide

6. SI Base Units QuantitySI UnitSymbol length/distancemeterm timeseconds masskilogramkg amount of substance molemol temperatureKelvinK

7. Common Conversions 1 meter = 3.281 feet 1 kilometer = 0.6214miles 1 kilogram = 2.205 pounds 1 liter = 33.81 US fluid ounces

8. Prefixes and base units Prefixes are added to base units to express small or large quantities –1 millimeter is 1/1000 of a meter or 1 m = 1000 mm –1 kilometer is 1000 meters or 1 km = 1000 m –Which unit would you use to measure the width of the nail on your pinky finger? –Which unit would you use to measure the distance from San Diego to Las Vegas?

9. PrefixSymbolFactorScientific Notation GigaG1,000,000,00010 9 MegaM1,000,00010 6 kilok1,00010 3 hectoh10010 2 decada or dk1010 1 1 decid0.110 -1 centic.0110 -2 millim.00110 -3 microµ0.00000110 -6 nanon0.00000000110 -9 picop0.00000000000110 -12

10. Conversions: Convert: –5000 milliliters (mL) to liters (L) –0.0250 kilograms (kg) to grams (g) –0.625 seconds (s) to milliseconds (ms) –880 centimeters (cm) to meters (m)

11. Derived Units Certain quantities cannot be measured in base units A unit that is formed from a combination of units is called a derived unit: –Volume (mL or cm 3 ), speed (m/s), density (g/mL or g/cm 3 )

12. Volume Volume is the space occupied by an object or substance Units –solids: cm 3 –liquids: mL *Note: 1 cm 3 = 1 mL Graduated cylinders are often used to measure the volume of liquids

13. Determining Volume for Regular Solid Object cube V = s 3 rectangle V = l x w x h cylinder V= hπr 2

14. Determining the Volume of an Irregular Solid How would you find the volume of a rock? Displacement: –The amount of water goes up is equal to the volume of the rock

15. Density Density is defined as how much matter occupies a certain amount of space Units –Liquids: g/mL –Solids: g/cm 3 A pure substance will always have the same density –All samples of pure aluminum have a density of 2.7 g/cm 3 or D= M V density= mass volume

16. Gold (D = 19.7 g/cm 3 ) and aluminum ( D = 2.70 g/cm 3 ) Gold is more dense than aluminum If you have a block of gold and a block of aluminum that are the same size (volume) the gold block will be heavier Gold Aluminum V = 1 cm 3 M = 2.70 g V = 1 cm 3 M = 19.70 g

17. Temperature Temperature is a measure of the particle energy in a substance The Fahrenheit scale is used in the United States, but nearly all other countries use the Celsius scale –Celsius scale based on the freezing point (0  C) and boiling point (100  C) of water Scientists prefer the Kelvin scale because 0 K represents absolute zero, the coldest possible temperature

19. Lord Kelvin The Kelvin (K) is the SI unit for temperature To convert between Kelvins and o C –K to o C : temperature in Kelvins - 273 288 K - 273 = 15 o C – o C to K : temperature in o C + 273 23 o C + 273 = 296 K