SCIENTIFIC MEASUREMENT

QUALitative Measurements descriptive, non-numeric results: hot / cold heavy / light etc. often influenced by the measurer’s perception

QUANTitative Measurements definite results – typically numbers with units: 100 °C 32 °F 30 mL 11.4 g/cm3

QUANTitative Measurements definite results – typically numbers with units: only as accurate as the instrument and method used to measure

Accuracy and Precision accuracy - how close your measurement is to the true value precision - how close values in a series of measurements are to one another

Significant Figures Math: exact numbers 1 = 1.00 = 1.000000 Science: numbers are measured data – limited in the number of usable digits, or significant figures

Significant Figures The sig figs in a measurement include all the known digits, plus one last digit that is estimated. When doing a calculation, the sig figs in the answer depend on the sig figs used in the calculation.

Significant Figures: Rules Every non-zero digit is significant. Zeros between non-zero digits are significant. ex: 2008 15.08

Significant Figures: Rules Zeros in front of significant digits are not significant. ex: 0.04 0.00079

Significant Figures: Rules Zeros at the end of a number & after a decimal pt are significant. Zeros at the end of a number without a decimal point are not significant. ex: 690,000 120 14.00

Significant Figures: Rules Exact or counted numbers have unlimited significant figures. ex: number of students in class number of eggs in a dozen 12 eggs, or 12.00000000… to infinity

Significant Figures: Rules