Technical Science Scientific Tools and Methods

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Technical ScienceScientific Tools and Methods

• The Metric System

From Southwest Wisconsin Technical College
http//www.swtc.edu8082/mscenter/mthsci/science/1
tools/p02amtrc.pps
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The Metric System

• In this section you will
• Describe the features of a measurement system
• Describe the benefits of the Metric System
• Make metric conversions
• Make metric measurements

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Measurement Systems
Home

• Any measurement system will have three features.

• Standard Units
• Additional units for measuring large and small
  quantities
• Relationships between units of measure

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Measurement Systems
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• Standards are units of measure that are the same
  no matter where you go.

• A foot represents the same distance everywhere in
  the US. A foot is a standard unit of length.
• Since everyone agrees on the value of a standard,
  they insure that measurements are consistent.

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Measurement Systems

• You will want to make other measurements besides
  length. A standard is necessary for each type of
  measure you want to make.

Measurement English Metric Length Foot Meter W
eight Pound Gram Capacity Gallon Liter etc
etc etc
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Measurement Systems

• A foot is a standard unit of length. But, it is
  not a good unit for measuring all lengths.

• You could measure the room or a table in feet.
  But it would not make sense to measure a blood
  cell or the distance between two cities in feet.
• A measurement system must have additional units
  to measure very large and very small amounts.

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Measurement Systems

• What are some of the additional units of measure
  for length, weight, and capacity in the English
  system?

Length Inch, Foot, Yard, Mile,
etc Weight Ounce, Pound, Ton, etc Capacity Cup,
Pint, Quart, Gallon, Barrel, etc
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Measurement Systems

• Finally, measurement systems must have
  relationships between the units of measure.

• Since inches, feet, yards, and miles are all
  measurements of length then you should be able to
  convert from one to another.
• There are 12 inches in one foot. There are 3
  feet in one yard. There are 1760 yards in a
  mile. These relationships are constant. This
  allows us to convert from one unit to another.

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Measurement Systems
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• What are the three requirements for a measurement
  system?

• There must be standards for every type of
  measurement you want to make.
• There must be additional units for measuring
  large and small quantities.
• There must be a relationship between the units of
  measure.

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Benefits of the Metric System
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• Any measurement system will have three features
• Standard Units
• Additional units for measuring large and small
  quantities
• Relationships between units of measure

• If both the English system and the Metric system
  have all the requirements for a measuring system,
  why should we switch to the metric system?
• To answer this question, lets see how convenient
  the English system is to work with.

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Benefits of the Metric System

• Lets say you were asked the following question
  How many inches are in one mile?

• To answer this question you would need some of
  the information that follows.
• 12 inches 1 foot 3 feet 1 yard
• 5280 feet 1 mile 1760 yards 1 mile
• Now you can see one problem with the English
  system. There is no consistent relationship
  between the units in the English system.

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Benefits of the Metric System

• There is no consistent relationship between the
  units in the English system.

• There are 12 inches in 1 foot. There are 3 feet
  in 1yard and there are 5280 feet in 1 mile.
• This inconsistency makes converting in the
  English system very difficult for two reasons.
• You have to remember all those different
  conversions.
• Calculating with those peculiar numbers can be
  time consuming even with a calculator.

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Benefits of the Metric System

• The Metric system has a consistent relationship
  between units.

• This means that as you move from one unit to the
  next larger or smaller you always change by the
  same factor.
• In the Metric system the factor by which you
  change is 10. This makes the Metric system a
  base-ten system.
• The next slides will explain this in more detail.

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Benefits of the Metric System

• Our monetary system is an example of a familiar
  base-ten system.

• Dollar ltgt Dime ltgt Penny
• As you go from one unit to the next larger or
  smaller, you are changing by a factor of ten.
• 10 pennies 1 dime 10 dimes 1 dollar.
• 1 penny 0.1 dimes 1 dime 0.1 dollars

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Benefits of the Metric System

• Converting between units in a base ten system is
  very easy. Dollar ltgt Dime ltgt Penny

• To convert from a unit to the next smaller unit,
  multiply by 10
• 2 dollars 20 dimes (2 x 10 20).
• 5 dimes 50 pennies (5 x 10 50)
• To convert from a unit to the next larger unit,
  divide by 10.
• 30 pennies 3 dimes (30 ? 10 3)
• 60 dimes 6 dollars (60 ? 10 6)

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Benefits of the Metric System

• What if you had to convert from pennies to
  dollars or dollars to pennies?
• Dollar ltgt Dime ltgt Penny

• Dollars and Pennies are two positions apart.
• Each position change represents a factor of 10.
• 2 positions are 2 factors of 10 or 100 (10 x 10
  100)
• Multiply to convert from a larger to a smaller
  unit.
• 3 dollars 300 pennies (3 x 100 300)
• Divide to convert from a smaller to a larger
  unit.
• 700 pennies 7 dollars (700 ? 100 7)

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Benefits of the Metric System

• Converting in a base ten system is just a matter
  of multiplying or dividing by a factor of 10.
  (Factors of 10 10, 100, 1000, 10,000 etc.)

• A fast way to multiply or divide by a factor of
  ten is to move the decimal.

5.623 x 100
5 6 2 3
45.92 ? 10
4 5 9 2
.
.
.
.
.

• Multiply by 100, move the decimal 2 places to the
  right

• Divide by 10, move the decimal 1 place to the left

• Since the Metric System is base ten, you can
  convert units by simply moving the decimal point.

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Benefits of the Metric System
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• Another benefit of the Metric System is the fact
  that that the whole world uses it. (except the
  US)

• All fields of science use only the Metric System.

• In order for a measurement system to be useful
  everyone must agree on the standards that make it
  up.
• The more people that agree on those standards the
  better the system will be.

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Benefits of the Metric System

• You might be wondering If the Metric system is
  so great why dont we use it in the US.

• The truth is that we do use the metric system.
• You have probably bought a 2 liter bottle of soda
• Your car has many metric parts
• The aspirin you take is measured in milligrams.
• The US is in the middle of a very slow process of
  converting to the Metric system.
• As time goes by, the metric system will become a
  bigger part of your life.

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Benefits of theMetric System
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• Why should US companies be concerned about
  switching to the Metric System?

• If they want to sell products to other countries
  they have to use their standards of measure.
• It is probably more expensive to use two
  different measurement systems.
• If some parts are produced in another country
  will they be compatible with parts produced here?

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Making Metric Conversions
Home

• Study the table below to become familiar with
  metric units of measure.

Back
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Making Metric Conversions

• Answer the following questions. Use the button
  below to refer to the Table of Metric Prefixes.

• What is the base unit of measure for ...
• Length
• Mass
• Volume

• Meter
• Gram
• Liter

Table
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Making Metric Conversions

• Name the following units of measure. Use the
  prefix followed by the base unit.
• 1,000 meters
• 0.001 liters
• 0.01 meters
• 10 gram

• Kilometer
• Milliliter
• Centimeter
• Dekagram

Table
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Making Metric Conversions

• You probably noticed that the metric prefixes
  stay the same no matter what unit of measure you
  use.

• Length in the English system is measured in
  inches, feet, yards, miles etc. but volume is
  measured in ounces, cups, quarts, gallons, etc.
• In the metric system kilo is always 1,000 base
  units. It doesnt matter what you are
  measuring.
• 1000 grams is a kilogram. There are a lot less
  metric units to remember.
• This is another benefit of the Metric System.

Table
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Making Metric Conversions

• Name the unit when given the abbreviation and
  vice versa. Metric abbreviations use small case
  letters and no periods.
• km Mililiter
• mg Kilogram
• cm Decimeter
• Dekagram
  

• Kilometer
• Milligram
• Centimeter
• Megagram
• Microgram

• ml
• kg
• dm
• dag

Table
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Making Metric Conversions

• Now that you are familiar with metric units, you
  can make some conversions.

• To make conversions within the Metric System, you
  have to answer two questions.
• First, how many positions is it from the starting
  unit to the unit you want to convert to? Since
  the metric system is base ten, this tells how
  many places to move the decimal.
• Second, are you converting from a larger unit to
  a smaller unit or from a smaller unit to a larger
  unit? This tells which way to move the decimal.
  

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Making Metric Conversions

• 4.5 kilometers meters.

4 5 0 0
.
.
.
.

• It is 3 positions from the starting unit (kilo)
  to the unit we want to convert to (base unit -
  meter).

• We are converting from a larger unit to a smaller
  unit.
• We need more small units than large units to
  make up the same amount of distance.
• This means moving the decimal three places to the
  right.

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Making Metric Conversions
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• 8.3 grams milligrams.

8 3 0 0
.
.
.
.

• It is 3 positions from the starting unit (gram)
  to the unit we want to convert to (milli).

• We are converting from a larger unit to a smaller
  unit.
• We need more small units than large units to
  make up the same amount of mass.
• This means moving the decimal three places to the
  right.

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Making Metric Conversions
.
.

• 25,000 centimeters
  kilometers.

.
.
.
.
0
2 5 0 0 0

• It is 5 positions from the starting unit (centi)
  to the unit we want to convert to (kilo).

• We are converting from a smaller unit to a larger
  unit.
• We need fewer large units than small units to
  make up the same amount of distance.
• This means moving the decimal five places to the
  left.

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Making Metric Conversions

• 75 milliliters liters

.
.
0
0
7 5
.
.

• It is 3 positions from the starting unit (milli)
  to the unit we want to convert to (base unit -
  liter).

• We are converting from a smaller unit to a larger
  unit.
• We need fewer large units than small units to
  make up the same amount of volume.
• This means moving the decimal three places to the
  left.

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Making Metric Conversions
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• Make the following metric conversions.
• 1,000 grams kg
• 500 mg g
• 2.25 liters ml
• 0.07 g kg
• 1 kilometer m
• 450 ul ml
• 650 cm m
• 0.30 kg mg

• 1
• 0.5
• 2250
• 0.00007
• 1000
• 0.450
• 750,000
• 6.5
• 300,000

Table
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Making MetricMeasurements
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• Now you can make metric conversions but can you
  answer the questions below?

• You need 5 kilograms of potatoes from the store,
  can you carry them or should you take your car?
• A label on a bottle of cough syrup reads give 5
  milliliters as needed. Will 5 milliliters fit in
  a teaspoon or will you need a tablespoon?
• You are running a 1600 meter race. Is this a
  sprint or a distance event?

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Making MetricMeasurements

• Using the metric system isnt just about
  converting. You need to have a feel for the
  size of units you are working with.

• The English system is familiar to you. You have
  an idea about how heavy 5 pounds is but you
  probably dont have that same feeling for 5
  kilograms.
• The best way to get familiar with the metric
  system is to use it to make measurements.

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Making MetricMeasurements - Length

• The following are approximations to help you get
  a feel for metric units of length. We will deal
  only with the most common units.

• 1 kilometer ? Just over one half mile
• 1 meter ? Just over one yard
• 1 centimeter ? Width of your little fingernail
• 1 millimeter ? Thickness of your fingernail

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Making MetricMeasurements - Length

• Choose the most appropriate measure.

• Length of a football field
• 1 km, 100 m, 10 cm, 100 mm
• Length of a newborn baby
• 0.5 m, 0.05 km, 5,000mm, 50 cm
• Thickness of a sheet of paper
• 0.1 mm, 0.1 cm, 0.01 m, 1 km,

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Making Metric Measurements - Length

• The diagram below is part of a metric tape
  measure. The numbered divisions are centimeters.
  The small divisions are millimeters

• 10 Millimeters
• 100 Centimeters
• No
• Too large

• How many millimeters are in 1 cm?
• How many centimeters are in 1 m?
• Is the diagram drawn to scale?
• Are the units too large or too small?

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Making Metric Measurements - Length
A

• Measure Line A in mm, cm, and m. (Hint make
  your initial measurement in mm then convert.)

• You have gone 99 cm and 2 mm.

• 99 cm 990 mm

• 2 mm

• 992 mm gt

• 99.2 cm gt

• 0.992 m

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Making Metric Measurements - Length
B

• Measure Line B in mm, cm, and m.

• You have gone 1 m, 2 cm, and 7 mm.
  

• 1m 100 cm 1000 mm

• 2 cm 20 mm

• 7 mm

• 1027 mm gt

• 102.7 cm gt

• 1.027 m

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Making Metric Measurements - Length
1
2

• Measure Line 1 and 2 in mm, cm, and m.

• 1004 mm gt

• 100.4 cm gt

• 1.004 m

• Line 1
• Line 2

• 979 mm gt

• 97.9 cm gt

• 0.979 m

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Making Metric Measurements - Length
3
4

• Measure Line 3 and 4 in mm, cm, and m.

• 2015 mm gt

• 201.5 cm gt

• 2.015 m

• Line 3
• Line 4

• 1998 mm gt

• 199.8 cm gt

• 1.998 m

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Making MetricMeasurements - Mass

• The following are approximations to help you get
  a feel for metric units of mass. We will deal
  only with the most common units.

• 1 kilogram ? Just over 2 pounds
• 1 gram ? Mass of a raisin
• 1 milligram ? Mass of a grain of sand

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Making MetricMeasurements - Mass

• Choose the most appropriate measure.

• Mass of a nickel
• 50 g, 5 mg, 0.5 kg, 5 g, 500 mg
• Mass of an aspirin
• 500 mg, 0.5 mg, 500 g, 50 kg, 50 g
• Mass of an average adult
• 700 kg, 0.7 g, 700 mg, 7,000 g, 70 kg
• Mass of a baseball
• 400 mg, 0.4 g, 4 kg, 400 g, 40 g

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Making Metric Measurements - Mass

• Mass is measured using a balance. The object to
  be measured is placed in one pan and standard
  mass units are placed in the other pan.

• 1000 Milligrams
• 1000 Grams

• How many milligrams are in 1 g?
• How many grams are in 1 kg?

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Making Metric Measurements - Mass

• Measure Object A in g, mg, and kg.

• Put standard mass units in the pan until it
  balances.

• 50 g

• 20 g

• 10 g

• 80 g gt

• 80,000 mg gt

• 0.080 kg

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Making Metric Measurements - Mass

• Measure Object B in g, mg, and kg.

• Put standard mass units in the pan until it
  balances.

• 50 g

• 50 g

• 10 g

• 110 g gt

• 110,000 mg gt

• 0.110 kg

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Making Metric Measurements - Mass

• Measure Object 1 in g, mg, and kg.

• Put standard mass units in the pan until it
  balances.

• 130,000 mg gt

• 0.130 kg

• 130 g gt

• Object 1

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Making Metric Measurements - Mass

• Measure Object 2 in g, mg, and kg.

• Put standard mass units in the pan until it
  balances.

• 60,000 mg gt

• 0.060 kg

• 60 g gt

• Object 2

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Making MetricMeasurements - Volume

• The following are approximations to help you get
  a feel for metric units of volume. We will deal
  only with the most common units.

• 1 liter ? Just over 1 quart
• 1 milliliter ? About 20 drops

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Making MetricMeasurements - Volume

• Choose the most appropriate measure.

• Volume of a cars gas tank
• 50 l, 5 l, 500 ml, 50 ml, 500 l
• Volume of a teaspoon
• 0.5 l, 0.5 ml, 5 l, 5 ml, 500 ml
• Volume of a can of soda
• 500 l, 0.05 l, 500 ml, 0.5 ml, 0.005 ml
• Volume of a syringe
• 0.02 ml, 200 ml, 0.02 l, 2 l, 2 ml

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Making Metric Measurements - Volume

• Volume can be measured using beakers that are
  designed to hold a standard amount of fluid.

• 1000 Milliliters
• False

• How many milliliters are in 1 liter?
• Do the small divisions represent the same volume
  on each beaker?

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Making Metric Measurements - Volume

• Measure the volume of water in the beaker in ml
  and l

• There are 5 divisions between 0 ml and 250 ml.
• Each division is 50 ml (250 ? 5).

• You have gone past 500 ml and 2 more divisions.

• 500 ml

• 2 divisions 100 ml

• 600 ml gt

• 0.6 liters

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Making Metric Measurements - Volume

• Measure the volume of water in the beaker in ml
  and l

• There are 5 divisions between 0 ml and 50 ml.
• Each division is 10 ml (50 ? 5).

• You have gone past 50 ml and 4 more divisions.

• 50 ml

• 4 divisions 40 ml

• 90 ml gt

• 0.09 liters

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Making Metric Measurements - Volume
1

• Measure the volume of water in Beakers 1 2 in
  ml and l

• 60 ml gt

• 0.06 liters

• Beaker 1
• Beaker 2

2

• 850 ml gt

• 0.850 liters

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Making MetricMeasurements

• Now you should be able to make metric conversions
  and you should have some feel for size of metric
  units.

• Getting used to the metric system doesnt happen
  all at once. You need to use it.
• Make note of the metric measurements that are
  around you.
• All items in the grocery store have metric
  measures.
• Your cars speedometer has a metric scale
• Your tape measure and kitchen measuring cups have
  both a Metric and an English scale

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Making MetricMeasurements
Home

• Name at least three benefits of the Metric
  System.

• There is a consistent relationship between units.
  Prefixes stay the same.
• There arent a lot of conversion factors to
  remember. Its easy to convert.
• The whole world uses it.

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Technical ScienceScientific Tools and Methods
You have completed The Metric System