Transcript  460,000,000,000,000,000,000,000   Dimensional Analysis How many pizzas do you need to order if 32 people will attend a party, each person eats 3 slices.

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460,000,000,000,000,000,000,000
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Dimensional Analysis
How many pizzas do you need to order if 32
people will attend a party, each person eats 3
slices of pizza, and each pizza has 8 slices?
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Uncertainty
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Accuracy
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Precision
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Using tools to make
measurements
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1. Zeros between nonzero digits are always
significant.
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1005 kg – Has 4 significant figures
2. Zeros at the beginning of a number are never
significant.
0.02 g – Has one sig. fig.
 0.0025 - Has two sig. figs.
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3. Zeros at the end of a number are significant only
if there is a decimal in the number.
0.0200 g – Has three sig. figs.
 3.0 cm – Has two sig. figs.
 100 cm – Has only one sig. fig.
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When we use measured quantities to do calculations,
the least certain measurement limits the certainty of
our calculation.
Therefore the number of significant figures in our
answer is determined by the number of sig figs in the
least certain number.
Rules:
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For addition and subtraction: The answer has the same number
of decimal places as the number with the least amount of
decimal places.
20.42 + 1.322 + 83.1 = 104.842, we round to 104.8
For multiplication and division: The answer has the same
number of sig figs as the number with the smallest number of
sig figs.
6.221 x 5.2 = 32.3492, we round to 32
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Be concise
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Write in 3rd person (don’t use We or I)
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Use past tense when writing the procedure and
conclusion
Ex: The compound was weighed
Use present tense when writing the
purpose/Background section
Ex: The purpose of this experiment is…
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Be prepared
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Be organized
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Take good notes
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Write about what actually happened not what
should have happened.
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Purpose/Background
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Materials/Safety
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Procedure
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Data/Calculations
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Analysis/Conclusion
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Independent Variable
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Dependent Variable
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Creating a Data Table