Significant Digits

I. Recognizing Sig. Digs on Instruments Measuring is essential when collecting data Precision (getting the same number each time) has a lot to do with uncertainty To be precise (decrease uncertainty) you should measure: Carefully and more than once Estimate to one digit beyond the smallest mark on the instrument

II. Recognizing Sig. Digs on Paper A. Basic Rules: Any number 1-9 is considered significant Zeros are significant if they: Terminate the number to the right of the decimal They are “sandwiched” between two significant digits

II. Recognizing Sig. Digs on Paper B. Advanced Rules: Calculations When Adding or Subtracting: your answer should be rounded to match the measurement with the LEAST no. of DECIMAL PLACES When Multiplying or Dividing: your answer should be rounded to match the measurement with the LEAST no. of SIGNIFICANT DIGITS

I. Recognizing Sig. Digs on Instruments Measuring is essential when collecting data Precision (getting the same number each time) has a lot to do with uncertainty To be precise (decrease uncertainty) you should measure: Carefully and more than once Estimate to one digit beyond the smallest mark on the instrument PRACTICE/EXAMPLES:

I. Recognizing Sig. Digs on Instruments PRACTICE/EXAMPLES: How many sig digs? a.) 3.57 b.) 288 c. )20.8 d.) 0.01 e.)0.010 f.)0.0100 A. Basic Rules: Any number 1-9 is considered significant Zero are significant if they: Terminate the number to the right of the decimal They are “sandwiched” between two significant digits

II. Recognizing Sig. Digs on Paper B. Advanced Rules: Calculations When Adding or Subtracting: your answer should be rounded to match the measurement with the LEAST no. of DECIMAL PLACES When Multiplying or Dividing: your answer should be rounded to match the measurement with the LEAST no. of SIGNIFICANT DIGITS PRACTICE/EXAMPLES: a) 37.24 mL + 10.3 mL = 47.5 4mL calculator value 1.23 cm * 12.34 cm = 15.1782 cm2