Topic: The Metric System Do Now: Calculate the volume of Fe. What element is Fe? mass of Fe(s) = 15.9 g density of Fe(s) = 7.87 g/cm3

Measurement up to 1790: Not a pretty picture! standard Measurement requires standard and until 1790’s every region had own standard

Systeme International (SI) created French Academy of Sciences created the metric system in 1790* – Originally, earth-based standards – Volume & mass linked to length – Larger & smaller multiples of each unit related by powers of 10 = metric system *updated every few years (particularly in in 1960 and 1991)

Standards “standard: something used as comparison for measuring” – standard must: available for everyone be available for everyone to use to check measurements be something in nature that is same everywhere be something in nature that is same everywhere never vary never vary

second What is a second? defined in terms of electron transitions in Cs-133 (Caesium – an element)

What is a meter? / distance light travels in vacuum in 1/299,792,458 th of second

Liter What is a Liter? defined as cube measuring 10 centimeters on each side (1000 cm 3 ) Liter based on meter, which is based on Earth 10 cm

kilogram What is a kilogram? 10 cm defined as mass 1 Liter water at 4°C Why water Why water? kilogram is based on liter, which is based on meter, which is based on Earth

For Water only:

kilogram Prototype kilogram stored in vault in France

Smaller Units 1/10 of a meter = decimeter (dm) 1/100 of a meter = centimeter (cm) 1/1000 of a meter = millimeter (mm) Larger Units 10 meters = dekameter (dam) 100 meters = hectometer (hm) 1000 meters = kilometer (km)

UsePowerValueSymbolPrefix Gigabyte ,000,000,000 GGiga Megamillion ,000,000MMega kilometer ,000kKilo decimeter ddeci centimeter ccenti millimeter mmilli micrometer  micro nanometer nnano Prefixes in the SI System Don’t copy…. where can you find?

Fundamental or Base Units Based on object or event in nature 7 The SI system has 7 fundamental units *label on Ref table

AbbreviationNameQuantity mmeterLength kgkilogramMass KkelvinTemperature ssecondTime cdcandela Luminous Intensity Aampere Electric Current molMole Amount of Substance 7 Fundamental Quantities of SI

Derived Units Combinations of fundamental units Examples: – Speed – Speed (meters/second) – Area – Area (Length x Width) – Volume – Volume (Length x Width x Height) – Density – Density (Mass / Volume)

Prefixes prefixes can be used with all 7 fundamental units! meter – Kilometer liter – Milliliter gram – Centigram second – Microsecond kelvin – Nanokelvin

Jefferson Proposed decimal-based measurement system for United States Didn’t have prefix idea and system had too many names….and so we are stuck using feet, inches, cups, ounces, etc…

Kids Have Dropped Dead Converting Metric

KILO 1000 Units HECTO 100 Units DEKA 10 Units DECI 0.1 Unit CENTI 0.01 Unit MILLI Unit Meters Liters Grams Ladder Method How do you use the “ ladder ” method? 1 st – Determine your starting point. 2 nd – Count the “ jumps ” to your ending point. 3 rd – Move the decimal the same number of jumps in the same direction. 4 km = _________ m How many jumps does it take? Starting Point Ending Point 4. 1 __. 2 3 = 4000 m