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Introduction to the Metric System. Measurement by design. History. Created during French Revolution in 1790‘s 1793 French King Louis XVI beheaded National Assembly of France sets up new government French Academy of Science told to design new system of weights and measures
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Introduction to the Metric System Measurement by design
History • Created during French Revolution • in 1790‘s • 1793 French King Louis XVI beheaded • 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 • Called Systeme International d’Unitès, • or SI - International System of Units • Revised periodically • by International Bureau of Weight and Measures
Customary Units of Measurement • The English or Imperial 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 • Typical Units • length - inch, foot, yard, mile • weight/mass - ounce, pound • volume - teaspoon, cup, quart, gallon • temperature - degrees Fahrenheit • time - minutes, hours
Advantages of Using the Metric System • Universal - Used all around the world • Used in the scientific community and is the only accepted form of measurement • Used by the Olympics and International Sporting events. • Used by all industrialized nations • except United States • U.S. loses billions of dollars in trade
Advantages of Using the Metric System • Simple to use • A few base unitsmake up all measurements • length - metre • mass - grams • volume - litres • temperature – degrees Celsius • time - seconds
Advantages of Using the Metric System • There is one standard 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
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.”
Units of Length • Length - the distance between two points • standard unit is metre(m) • long distances are measured in km • Measured using a metrestick or ruler
Prefixes and Units of Length • centimetre- cm • 1 m = 100 cm • 1 cm = 1/100th m • millimetr e- mm • 1 m = 1000 mm • 1 mm = 1/1000th m • 10 mm = 1 cm • measures very small lengths • kilometre- km • 1 km = 1000 m • 1 m = 1/1000th km • measures long distances
Measuring Mass • Mass - the quantity of matter in an object • standard unit is gram(g) • Measured using a digital scale or triple beam balance
Measuring Volume and Capacity • Volume - the amount of space occupied by an object • standard unit is litre(L) • 1 L = 1000 ml = 1000 cm3 = 1 dm3 • Measured using a graduated cylinder • Capacity - a measure of the volume inside a container
Prefixes and Units of Volume • Litre- L • 1 L = 1000 milliliters • 1 L = 1000 cubic centimeters = 1000 cm3 • millilitre- mL • measures small volumes • 1 mL = 1 cubic centimeter • 1000 mL = 1 Liter • 1 mL = 1/1000th liter • kilolitre - kL • measures large volumes • 1 kL = 1000 L The SI unit for volume is NOT the litre, it is a Cubic metre. Litre are accepted as an SI derived unit.
Measuring Volume • 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.
Displacement • Displacement • Amount of water an object replaces • Equal to its volume
Volume of a Solid, Irregular Object • Displacement - amount of water an object replaces • Procedure • Place graduate beaker beneath spout • Fill the overflow canwith water until water begins to spill • Empty the excess water • Place object to be measured into the overflow can • Remove when water stops flowing out of the can • Measure the displaced water using a graduated cylinder.
Volume of a Solid, Irregular Object • Displacement • Calculate the difference between the initial and final volume measurement.
Volume of a Solid, Regular Object • Volume -length x width x height • V = 2.8 cm x 3.2 cm x 2.5 cm • V = 22.4 cm3 • Measured with a ruler
Calculating Density • 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
Measuring Time • Time • metric unit is second (s)
Measuring Temperature • Temperature - the degree of “hotness” of an object • standard unit is celsius (°C) • measured with a thermometer
Temperature Conversions • Conversion Between Fahrenheit, Celsius, and Kelvin • Example: • Convert 75 ºC to ºF • Convert -10 ºF to ºC
Measurement Unit Conversion • You can convert between units of measurement • within the metric system • between the English system and metric system
Measurement Unit Conversion • You can convert between units of measurement • within the metric system • between the English system and metric system
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!
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.
Dimensional Analysis : The Rules of Unit Conversion. • Start with the given information… • Then set up your unit factor… • See that the original unit cancels out… • Then multiply and divide all numbers…
Unit Conversion Practice • Example:Convert 12 gallons to units of quarts.
Unit Conversion Practice • Example:Convert 4 ounces to kilograms.