Significant Figures

Significant Figures 8/15/13

Bellwork (8/15/13) • What is a Domino? • It is a method for converting a unit of measurement into another unit of measurement

Significant Figures • Significant Figures (sig. figs.): the number of digits that carry meaning contributing to the precision of a measurement or calculated data.

Important Note!!! • In-class notes are ONLY slides 14, 17, 18 and 19!

Precision and Accuracy Low AccuracyHigh Precision High AccuracyHigh Precision High AccuracyLow Precision

Significant Figures • Significant figures, which are also called significant digits, are very important in science. • Each recorded measurement has a certain number of significant figures. • Calculations done on these measurements must follow the rules for significant figures.

Significant Figures • The significance of a digit has to do with whether it represents a true measurement or not. • Any digit that is actually measured or estimated will be considered significant. • Placeholders, or digits that have not been measured or estimated, are not considered significant.

Significant Figures • There are 5 rules to determine which zeros in a number are significant or not.

Rules for Significant Figures • Rule #1: All non-zero digits (1-9) are significant.For example:453 number of sig figs______ 345.21 number of sig figs______

Rules for Significant Figures • Rule #2: Zeros between non-zero digits are significant.For example: 12.007 number of sig figs______ 3008007 number of sig figs______

Rules for Significant Figures • Rule #3: Zeros to the left of the first non-zero digit are NOT significant.For example:1.02 number of sig figs______0.12 number of sig figs______0.00127 number of sig figs______ 0.00040301 number of sig figs______

Rules for Significant Figures • Rule #4: If a number ends in zeros to the right of the decimal point, those zeros are significant.For example: • 2 number of sig figs______ 2.0 number of sig figs______ 2.00 number of sig figs______2.000 number of sig figs______ {This signifies greater precision.}

Rules for Significant Figures • Rule #5: If a number ends in zeros, the zeros to the right are NOT significant IF there is NO decimal point present.For example:47100 number of sig figs______ 20060 number of sig figs______ 40000 number of sig figs______

The Atlantic - Pacific Rule for Significant Figures • When determining the number of significant figures ask the question: • “Does the number have a decimal point?” (YES or NO answer) • If YES, then think of “P” for Present and the Pacific ocean • If NO, then think of “A” for Absent and the Atlantic ocean

The Atlantic and Pacific Rule for Significant Figures

The Atlantic and Pacific Rule for Significant Figures • "P" for "Present". This means that we imagine an arrow coming in from the Pacific ocean, from the left side • "A" for "Absent". This means that we imagine an arrow coming in from the Atlantic ocean, the right side.

The Atlantic and Pacific Rule for Significant Figures • Look for the first non zero number starting from that direction • That number, and all other numbers following it are considered to be significant • For “P” the numbers to the right of the first non zero number • For “A” the numbers to the left of the first non zero number

Ex 1) 0.020110 Ex 2) 730800 1) 48001 2) 9807000 3) 0.008401 4) 40.500 5) 64000 6) 64000. 7) 64000.00 8) 0.0107050 Sig. Figs. Practice

Ex 1) 0.020110 Ex 2) 730800 1) 48001 2) 9807000 3) 0.008401 4) 40.500 5) 64000 6) 64000. 7) 64000.00 8) 0.0107050 Ex 1) 0.020110 (5 sig. figs.) Ex 2) 730800 (4 sig. figs) 1) 48001 (5 sig. figs.) 2) 9807000 (4 sig. figs.) 3) 0.008401 (4 sig. figs.) 4) 40.500 (5 sig. figs.) 5) 64000 (2 sig. figs.) 6) 64000. (5 sig. figs.) 7) 64000.00 (7 sig. figs.) 8) 0.0107050 (6 sig. figs.) Sig. Figs. Practice

Significant Figures