Accuracy, Precision, Significant Figures General Physics
Accuracy The extent to which a measured value agrees with a standard value
Parallax Apparent shift in position when viewed at an angle Ex. Reading graduated cylinder above or below the water line Affects accuracy
Precision The degree of exactness of a measurement High precision if all numbers are close in value Ex. 18.2 cm, 18.3 cm, 18.25 cm
Accurate, Precise, Both, or Neither
Accurate, Precise, Both, Neither
Accurate, Precise, Both, Neither
Precision and Significant Digits The last digit of a measurement is an estimate, but is still significant
Precision of an Instrument Reflects the number of sig. digits in a reading All measurements made with the same instrument have same precision
Precision of an Instrument Reading is btwn. 5.3 and 5.4 cm. What is the precision of this ruler? Hundredths place
Significant Figures Used to report all precisely known numbers plus one estimated digit
Sig. Fig. Rules Every nonzero digit is significant Ex. 24.7, 237 (3 sig. figs.) Zeros between nonzeros are significant Ex. 7003, 40.07 (4 sig. figs)
Rules of Sig. Figs. Zeros appearing in front of nonzero digits are not significant -act as placeholders, show magnitude Ex. 0.000042, 0.34 (2 sig. figs.)
Rules of Sig. Figs Zeros at the end of a number and to the right of a decimal point are significant Ex. 43.60, 1.010 (4 sig. figs.)
Rules of Sig. Figs. Zeros at the end of the number without a decimal point aren’t significant Ex. 300 (1 sig. fig.), 27,300 (3 sig. figs.)
Sig. Fig. Shortcut 23.50 23,400 0.00560
Multiplication and Division with Sig. Figs. Your answer can’t have more sig. figs. than the number in the calculation with the least amount of sig. figs. Ex. Finding Area Length = 60.564278 m Width = 35.25 m Answer = 2135 m2, not 2134.8908 m2
Addition and Subtraction with Sig. Figs. Answers can’t have more numbers to the right of the decimal point than the number with the least amount of numbers to the right of the decimal point Ex. 22.03 + 23.1 = 45.1 Ex. 1600 + 12 + .02 = 1600