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Objectives:
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Use proper technique to make accurate and precise
measurements.
Apply the rules for significant figures to calculations.
• Informal Assessment:
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Monitoring student interactions and questions as they
complete the measurement lab and significant figures practice
• Formal Assessment:
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Analyzing student responses to measurement lab and
significant figures practice
• Common Core Connection
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Use appropriate tools strategically
Attend to precision
Make sense of problem and persevere in solving them
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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

Determine the number of Sig Figs in the
numbers listed below
◦ 141
◦ 0.252
◦ 0.250

With your row, discuss the following
questions:
◦ Would you rather have Cheetos fingers, or a
popcorn kernel stuck in the back of your throat, for
the rest of your life?
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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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Finish Significant Figures Calculations WS
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Study for Significant Figures Quiz on 9/11
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Warm-Up
Measuring to the Correct Sig Figs
Measurement Lab Trial 2
Significant Figures Inquiry Wrap-Up
Significant Figures Practice
Significant Figures Calculations
Significant Figures Calculation Practice
Exit Ticket
Lab Equipment
Unit of Measurement
(cm, g, mL, etc.)
Number of Decimal
Places it Can be Read
to
Ruler/ Meter Stick
Balance
Beaker
Graduated Cylinder
Erlenmeyer Flask
Complete the table and if you are having trouble look at your trial 1
measurements from yesterday
Travel to the stations in the lab and measure the mass, volume
or length to the correct number of decimal places. DON’T Record
the number of sig figs in your trial 2 measurement. Record 3 of
your measurements on the board
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How do the trial 2 measurements differ from
the trial 1 measurements?
Why are significant figures important?
Wrap-Up of the Sig Fig Rules
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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
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52.3 has 3 sig figs
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There are 5 sig figs (start counting at 9)
How many sig figs in .0093077
•
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
• .0026702
m
-5
• 19.0750 kg
-6
• 25,000,000,
000 mm
-2
• 1,908,150
-6
• 520 ml
-2
• .0102 ns
-3
L
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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
 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
 .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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When doing calculations with significant
figures, conversion factors do not figure in
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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
Complete the practice at your desk. Problems
not completed in class will become your
homework.
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Complete the calculation to the correct
number of sig figs.
◦ 4.21
X
◦ 5.126
–
5.5270 =
2.2 =
Icebreaker:
◦ If you could turn yourself into something different
(car, animal, plant, etc) for one week, what would it
be?
◦ Would you rather be 4 inches tall or 100 ft tall?