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 Accuracy High Precision High Accuracy Low Precision High Accuracy High 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______ number of sig figs______

Rules for Significant Figures  Rule #2: Zeros between non-zero digits are significant. For example: number of sig figs______ 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______ number of sig figs______ 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:  2number of sig figs______ 2.0 number of sig figs______ 2.00number of sig figs______ 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: number of sig figs______ 20060number of sig figs______ 40000number 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

 "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

Sig. Figs. Practice Ex 1) Ex 2) ) ) ) ) ) ) ) )

Sig. Figs. Practice Ex 1) Ex 2) ) ) ) ) ) ) ) ) Ex 1) (5 sig. figs.) Ex 2) (4 sig. figs) 1) (5 sig. figs.) 2) (4 sig. figs.) 3) (4 sig. figs.) 4) (5 sig. figs.) 5) (2 sig. figs.) 6) (5 sig. figs.) 7) (7 sig. figs.) 8) (6 sig. figs.)