SCIENTIFIC MEASUREMENT
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Explore the differences between qualitative and quantitative measurements, accuracy, and precision in scientific data collection. Understand significant figures and their rules for precise calculations in various scientific fields.
SCIENTIFIC MEASUREMENT
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Presentation Transcript
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