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Understand the concepts of accuracy and precision in scientific measurements. Learn how to determine the number of significant figures in a given number using the Arrow Method.
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Significant Figures Aren’t all numbers important?!?!?!? Yes, but some are more significant than others…
What is accuracy? What is precision?
Accuracy / Precision • Accuracy – the agreement between a measured value and a true value. • Precision – agreement between several measurements of the same quantity.
Significant Figures • A measurement can only be as accurate and precise as the instrument that produced it. • A scientist must be able to express the accuracy of a number, not just its numerical value
Significant Figures • We can determine the accuracy of a number by the number of significant figures it contains.
The AMAZING sickles Arrow Method • If there IS a decimal point present, start on the left and draw an arrow to the right until you reach a NON-ZERO number.
The AMAZING sickles Arrow Method cont’d. • If there is NOT a decimal point present, start on the right and draw an arrow to the left until you reach a NON-ZERO number.
0.02 _____ 0.020 _____ 501 _____ 501.0 _____ 5,000 _____ 5,000. _____ 6,051.00 _____ 0.0005 _____ 0.1020 _____ 10,001 _____ 8040 ______ 0.0300 ______ 699.5 ______ 2.000 x 102 ______ 0.90100 ______ 90,100 ______ 4.7 x 10-8 ______ 10,800,000. ______ 3.01 x 1021 ______ 0.000410 ______ Determine the number of significant figures in the following numbers.