8 Classify as exact or measured: A red blood cell with diameter 6 x 10 -4cm.
9 Classify as exact or measured: There were six hats on the shelf.
10 Classify as exact or measured: A can of soda contains 355 mL of soda.
11 Uncertainty in Measurement The numbers reported in a measurement are limited by the measuring toolSignificant figures in a measurement include the known digits plus one estimated, or uncertain digit
12 This nail is 6.3 centimeters long for sure, but what exactly is the value of the hundredths place– 6.35, 6.36, 6.37?
13 “Significant figures in a measurement consist of all the digits known with certainty plus one final digit, which is somewhat uncertain or is estimated.”In the nail example, the hundredths place (3.36, the 6) is uncertain, or estimated.A SIGNIFICANT FIGURE IS NOT ALWAYS CERTAIN – THE LAST DIGIT OF ANY MEASUREMENT IS ESTIMATED!!!
14 Rules For Significant Figures All non-zero digits are significantExamples:significant figuressignificant figures
15 How many significant figures in 896.76 B. 3C. 4D. 5
16 Rules For Significant Figures 2) Zeros between numbers (sandwiched zeros) are all significantExample:304 – 3 significant digits– 5 significant digits
29 Sig Figs in Calculations A calculated answer cannot be more precise than the measuring tool.A calculated answer must match the least precise measurement.Significant figures are needed for final answers from1) adding or subtracting2) multiplying or dividing
30 Sig Figs and Addition/Subtraction The answer has the same number of decimal places as the measurement with the fewest decimal places.one decimal placetwo decimal places26.54answer one decimal place
31 Round the answer to the correct number of significant figures. 235 256.75256.8257
32 Round the answer to the correct number of significant figures 58 40.72540.7340.7
33 Multiplying and Dividing with Sig Figs Round (or add zeros) to the calculated answer until you have the same number of significant figures as the measurement with the fewest significant figures.