Imagine This!

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Imagine This!
Youre driving along a highway in Mexico when you
notice this sign
What should your speed be in miles per hour?
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Dimensional Analysis

• Equivalence Statements, Conversion Factors

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I) Equivalence Statements

• An equivalence statement shows two quantities
  with different units that are equal to each other.

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Equivalence Statements

• A) equivalence statements can be counted numbers
• Examples
• 1 dozen eggs 12 eggs
• 1 pair of shoes 2 shoes

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Equivalence Statements

• B) equivalence statements can be numbers with in
  the same measurement system
• Examples
• 1 km 1000m
• 5280 feet 1 mile

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Equivalence Statements

• C) equivalence statements can be numbers in
  different measurement systems
• Examples
• 1 lb 2.21 kg
• 1 in 2.540 cm

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Equivalence Statements

• D) equivalence statements can be numbers that are
  specific to a situation
• Examples
• 1 in 50 km such as on a map 1m 3.45cm such as
  in a photograph
• 3 students 1 lab group such as during a
  particular lab

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PracticeDesign four equivalence statements and
write them on your paper
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II) Conversion Factors

• A) Conversion factors are a set of fractions that
  ALWAYS equal one. The numerator and the
  denominator have equal value.

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II) Conversion Factors

• B) Every equivalence statement can be used to
  construct 2 conversion factors.

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• Practice
• Write the two conversion factors for the
  equivalent statement below
• equivalence statements
• 13 steps 1 flight of stairs

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II) Conversion Factors

• Use background information sheet (equivalent
  statements) to write base conversion factors.

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III) Using Conversion Factors for
Dimensional Analysis

• A) What happens to the value of a number when you
  multiply it by one?

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III) Using Conversion Factors for Dimensional
Analysis

• B) Because a conversion factor is a fraction that
  equals one, when it is used in a calculation it
  does not effect the value of the number, however,
  it does change the units.

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III) Using Conversion Factors for Dimensional
Analysis

• C) Dimensional analysis is the process by which a
  conversion factor is used to convert a value from
  one unit to another.

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III) Using Conversion Factors for
Dimensional Analysis

• D) To decide which of the two conversion factors
  to use make sure the units from the known value
  will cancel leaving units for the unknown value.

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DO IT!!
Convert 3.5 hours to minutes

1. Write down the given information and put it over
   1.

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DO IT!!

• Get up a conversion factor such that the
  information in the numerator and denominator
  equal each other.
• 3.5 hrs
• 1

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DO IT!!

• Cancel the units
• 3.5 hrs X 60 min
• 1 1 hrs

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DO IT!!

• Multiply the numerators.
• 3.5 hrs X 60 min 210 min
• 1 1hr

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DO IT!!

• Multiply the denominators
• 3.5 hrs X 60 min 210 min
• 1 1hr 1

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DO IT!!

• Divide your final answer and include the new
  units.
• 3.5 hrs X 60 min 210 min 210min
• 1 1hr 1

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Practice

• convert 27.5 L to mL

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Convert 67.9dam to m
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Convert 950g to kg