Topic: The Metric System Do Now: Calculate the volume of Fe 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! Measurement requires standard and until 1790’s every region had own standard

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

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

1790 – French Academy of Sciences created the metric system 3 Requirements

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)

Prefixes in the SI System Don’t copy…. where can you find? Use Power Value Symbol Prefix Gigabyte 109 1,000,000,000 G Giga Megamillion 106 1,000,000 M Mega kilometer 103 1,000 k Kilo decimeter 10-1 0.1 d deci centimeter 10-2 0.01 c centi millimeter 10-3 0.001 m milli micrometer 10-6 0.000001  micro nanometer 10-9 0.000000001 n nano

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

7 Fundamental Quantities of SI Abbreviation Name Quantity m meter Length kg kilogram Mass s second Time K kelvin Temperature mol Mole Amount of Substance cd candela Luminous Intensity A ampere Electric Current

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

Prefixes prefixes can be used with all 7 fundamental units! Kilometer Milliliter Centigram Microsecond Nanokelvin

1790 - 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…

What is a second? originally defined as 1/86,400th of average solar day Now: defined in terms of electron transitions in Cs-133 (Caesium – an element)

What is a meter? OLD WAY 1790: 1/10,000,000 th of distance from North pole to equator NEW WAY 1983: distance light travels in vacuum in 1/299,792,458 th of second

What is a Liter? defined as cube measuring 10 centimeters on each side (1000 cm3) Liter based on meter, which is based on Earth 10 cm 10 cm 10 cm

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

Prototype kilogram stored in vault in France

Kids Have Dropped Dead Converting Metric

How many jumps does it take? Ladder Method 1 2 3 KILO 1000 Units HECTO 100 Units DEKA 10 Units DECI 0.1 Unit Meters Liters Grams CENTI 0.01 Unit MILLI 0.001 Unit How do you use the “ladder” method? 1st – Determine your starting point. 2nd – Count the “jumps” to your ending point. 3rd – Move the decimal the same number of jumps in the same direction. 4 km = _________ m Starting Point Ending Point How many jumps does it take? 4. 1 __. 2 __. 3 __. = 4000 m