Measurement Lab 2 Significant Figures Calculations

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Measurement Lab 2Significant Figures Calculations
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• Objectives
• Use proper technique to make accurate and precise
  measurements.
• Apply the rules for significant figures to
  calculations.
• Informal Assessment
• Monitoring student interactions and questions as
  they complete the measurement lab and significant
  figures practice
• Formal Assessment
• Analyzing student responses to measurement lab
  and significant figures practice
• Common Core Connection
• Use appropriate tools strategically
• Attend to precision
• Make sense of problem and persevere in solving
  them

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Lesson Sequence

• Evaluate Warm-Up
• Explain Measuring to the Correct Sig Figs
• Elaborate Measurement Lab Trial 2
• Evaluate Significant Figures Inquiry
• Elaborate Significant Figures Practice
• Explain Significant Figures Calculations
• Elaborate Significant Figures Calculation
  Practice
• Evaluate Exit Ticket

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Warm - Up

• Determine the number of significant figures in
  the measurements below
• 5100
• 0.00520
• 7007
• 3.2400

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Objectives

• Today I will be able to
• Use proper technique to make accurate and precise
  measurements.
• Apply the rules for significant figures to
  calculations.

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Homework

• Finish Significant Figures Calculations WS
• Collect Data for STEM Fair

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Agenda

• Warm-Up
• Measuring to the Correct Sig Figs
• Measurement Lab Trial 2
• Significant Figures Inquiry
• Significant Figures Practice
• Significant Figures Calculations
• Significant Figures Calculation Practice
• Exit Ticket

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Draw this table on the back of your measurement
lab
Lab Equipment Unit of Measurement Number of Decimal Places it Can be Read to
Ruler/ Meter Stick
Balance
Beaker
Graduated Cylinder
Erlenmeyer Flask
Complete the table as Ms. Ose explains how to
take measurements using the correct number of
significant figures
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Measurement Lab Trial 2

• Travel to the stations in the lab and measure the
  mass, volume or length to the correct number of
  decimal places Record the number of sig figs in
  your trial 2 measurement. Record your answers on
  the poster on the board

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Class Discussion

• How do the trial 2 measurements differ from the
  trial 1 measurements?
• Why are significant figures important?

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Take out the Sig Fig Inquiry Worksheet

• Class review of Significant Figure Rules

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Significant Figure Practice

• Complete the practice at your desk.

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Significant Figure Notes
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Whats the SIGnificance?
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How many decimals can each ruler be read to?
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What volume of water is in the graduated cylinder?
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Which balance do you think costs the most and why?
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Significant Figure Calculations
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Atlantic Pacific Rule
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Atlantic Pacific Rule

• If a decimal point is Present as in 52.3 km,
  count from the Pacific Side from the first
  nonzero digit to the end. Meaning, count from
  the left side of the number
• - 52.3 has 3 sig figs
• - How many sig figs in .0093077
• - There are 5 sig figs (start counting at 9)

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Atlantic Pacific Rule

• If the decimal point is Absent, as in 1530 g,
  count from the Atlantic Side beginning with the
  first nonzero digit and going to the end,
  counting any zero as significant. This means
  start from the right
• - 1530 g has 3 sig figs
• How many sig figs in 190,542,100ml
• - There are 7 sig figs

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Examples

• .0026702 m
• - 5
• 19.0750 kg
• - 6
• 25,000,000,000 mm
• - 2

• 1,908,150 L
• - 6
• 520 ml
• - 2
• .0102 ns
• - 3

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Sig Fig Calculations

• You cannot be more precise than your least
  precise measurement
• In multiplication and division, the measurement
  with the smallest number of sig digits determines
  how many digits are allowed in the final answer
• If you have several steps, carry the extra
  digits. Only the final answer is rounded

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Examples

• 6.15 m x 4.026 m ?
• - 6.15 m has 3 sig figs
• - 4.026 m has 4 sig figs
• - Your answer can only have 3 sig figs
• - 24.7599 m2 ? 24.8 m2

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Examples

• .03287 g x 45.2 g ?
• - .03287 g has 4 sig figs
• - 45.2 g has 3 sig figs
• - Your answer can only have three sig figs
• - 1.485724 g ? 1.49 g

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Final Note

• When doing calculations with significant figures,
  conversion factors do not figure in
• Counts and defined numbers are EXACT and have no
  uncertain digits
• Example if you say there are 6 people in your
  family it is a counted number and is considered
  certain. There are not 6.1 people in your family
• Example 12 inches 1 foot is defined do not
  use significant figures. 1 foot will never be
  11.99 inches. In both cases, significant figures
  do not apply

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Significant Figures Calculation Practice

• Complete the practice at your desk. Problems not
  completed in class will become your homework.

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Exit Ticket

• Complete the calculation to the correct number of
  sig figs.
• 4.21 X 5.5270
• 5.126 2.2
• Icebreaker
• Would you rather have legs as long as your
  fingers or fingers as long as your legs?
• Would you rather win the lottery or live twice as
  long?