Accuracy and Precision EQ: In what ways do proper techniques contribute to reliable results?

Accuracy & Precision Distinguish between accuracy and precision in measurement Accuracy – extent to which a measurement approaches the true value of a quantity Agreement of a measurement with the accepted value of the quantity Precision – degree of exactness or refinement of a measurement How close a series of measurements are to one another.

What if she is inaccurate?

Accuracy vs Precision

Used to report all precisely known numbers + one estimated digit Significant Figures Used to report all precisely known numbers + one estimated digit

Rule #1 Every nonzero digit is significant Examples: 24 = 2 3.56 = 3 24 = 2 3.56 = 3 7 = 1

Rule #2 Zeros between non-zeros are significant Examples: 7003 = 4 7003 = 4 40.9 = 3

Rule #3 Zeros appearing in front of non-zero digits are not significant Act as placeholders Can’t be dropped, show magnitude Examples: 0.00024 = 2 0.453 = 3

Rule #4 Zeros at the end of a number and to the right of a decimal point are significant. Examples: 43.00 = 4 1.010 = 4 1.50 = 3

Rule #5 Zeros at the end of a number when no decimal point is present aren’t significant. Examples: 300 = 1 27,300 = 3

Special Rule Always remember PA P A If a decimal point is present, start on the Pacific (P) side and begin counting at the first non-zero digit all the way to the end. If a decimal is absent, start on the Atlantic (A) side and begin counting at the first non-zero digit all the way to the end.

Special Rule (cont.) Remember PA Examples: 123.003 = decimal present, start on “P” side, begin counting Answer = 6

Special Rule (cont.) Remember PA Examples: 204,000 = decimal absent, start on “A” side, begin counting at first non-zero digit until you hit the end of the number. Answer = 3

Sig. Fig. Math Rules Multiplication / Division: Your answer can’t have more sig. figs. than the number in the problem with the least amt. of sig. figs. Example = 60.56227892 x 35.25 Calculator says – 2134.890832 (wrong) Answer - 2135

Sig. Fig. Math Rules Addition / Subtraction: Answers can’t have more numbers to the right of the decimal point than the number in the problem with the least amt. of numbers to the right of the decimal point. Example = 24.1 + 3.35 + 2.23 Calculator says – 29.68 (wrong) Answer – 29.7

TOTD Record the answers to the questions below on side 2 of your TOTD sheet 1.) Express the following number in scientific notation: a. 365000 b. 0.0007801 2.) Using dimensional analysis convert 5.6 liters to pints. 3.) How many significant figures do the numbers below have? a. 231,000,000 b. 0.004012