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Introduction to the Metric System

Introduction to the Metric System. History. Created during French Revolution in 1790 French King overthrown National Assembly of France sets up new government French Academy of Science told to design new system of weights and measures Lavaiosie appointed to head committee. History.

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Introduction to the Metric System

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  1. Introduction to the Metric System

  2. History • Created during French Revolution • in 1790 • French King overthrown • National Assembly of France sets up new government • French Academy of Science told to design new system of weights and measures • Lavaiosie appointed to head committee

  3. History • Called Systeme International d’Unitès, • or SI - International System of Units • Revised periodically • by International Bureau of Weight and Measures

  4. Customary Units of Measurement • The English System • a collection of functionally unrelated units • Difficult to convert from one unit to another • Ex. 1 ft = 12 inches = 0.33 yard = 1/5280 miles • Customary Units • length - inch, foot, yard, mile • weight/mass - ounce, pound • volume - teaspoon, cup, quart, gallon • temperature - degrees Fahrenheit • time - minutes, hours

  5. Advantages of Using the Metric System • Universal - used everywhere • by all scientists to communicate • by all industrialized nations • except United States • U.S. loses billions of dollars in trade

  6. Advantages of Using the Metric System • Simple to use • A few base unitsmake up all measurements • length - meter • mass - grams • volume - liters • temperature – degrees Celsius • time - seconds

  7. Advantages of Using the Metric System • There is only one unit of measurement for each type of quantity • To simplify things, very small and very large numbers are expressed as multiples of the base unit. • Prefixes are used to represent how much smaller or larger the quantity is compared to the base unit. • Easy toconvert from one unit to another • shift decimal point right • shift decimal point left

  8. Advantages of Using the Metric System • Same set of prefixes for all units • Greek - multiples of the base • kilo -1000 × the base • hecto - 100 × the base • deka - 10 × the base • Latin - fractions of the base • deci - tenths of the base • centi -hundredths of the base • milli - thousandths of the base • Mnemonic: “Kids Have Dropped Over Dead Converting Metrics.”

  9. Metric Prefixes

  10. Units of Measurement • Length - the distance between two points • standard unit is meter(m) • long distances are measured in km • 1km = 1000m, 1 m = 1/1000th km • Small distances measured in cm or mm • 1 m = 100 cm , 1 cm = 1/100th m • 1 m = 1000 mm, 1 mm = 1/1000th m • 10 mm = 1 cm • Measured using a meter stick or ruler

  11. Units of Measurement • Mass - the quantity of matter in an object • standard unit is gram(g) • Measured using a digital scale or triple beam balance

  12. Units of Measurement • Volume - the amount of space occupied by an object • standard unit is liter(L) • 1 L = 1000 ml = 1000 cm3 = 1 dm3 • Measured using a graduated cylinder

  13. Units of Measurement • Measured with a graduated cylinder • Determine value of each mark on the scale • Read scale using the lowest position of the meniscus • Measure the meniscus at eye level from the center of the meniscus. • In the case of water and most liquids, the meniscus is concave. Mercury produces a convex meniscus.

  14. Units of Measurement • Density - a specific property of matter that is related to its mass divided by the volume. • D=M/V • the ratio of mass to volume • used to characterize a substance • each substance has a unique density • Units for density include: • g/mL • g/cm3 • g/cc

  15. Units of Measurement • Time • metric unit is second (s)

  16. Units of Measurement • Temperature - the degree of “hotness” of an object • standard unit is celsius (°C) • But scientists generally use the Kelvin Scale. • Based on absolute zero. • measured with a thermometer

  17. Temperature Conversions • Conversion Between Fahrenheit, Celsius, and Kelvin • Example: • Convert 75 ºC to ºF • Convert -10 ºF to ºC

  18. Conversion and the Metric System

  19. Measurement Unit Conversion • You can convert between units of measurement • within the metric system • between the English system and metric system

  20. Unit Conversion • Let your units do the work for you by simply memorizing connections between units. • Example: How many donuts are in one dozen? • We say: “Twelve donuts in a dozen.” • Or: 12 donuts = 1 dozen donuts • What does any number divided by itself equal? • ONE!

  21. Unit Conversion • This fraction is called a unit factor • Multiplication by a unit factor does not change the amount - only the unit. • Example:How many donuts are in 3.5 dozen? • You can probably do this in your head but try it using the Factor-Label Method.

  22. Unit Conversion Rules • Start with the given information… • Then set up your unit factor… • See that the original unit cancels out… • Then multiply and divide all numbers…

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