1. |
Every non-zero digist is signifcant Example: 3.2 mm has 2 sig figs
|
2. |
Trapped zeros are signifcant Example: 3002 mm has 4 sig figs
|
3. |
Zeros to the left of non-zero digits are not significant Example: 0.02 mm has 1 sig figs
|
4. |
Zeros to the right of a non-zero and with a decimal are significant Example: 320.0 mm has 4 sig figs
|
5. |
Zeros to the right of non-zero but without a decimal are not significant Example: 320 mm has 2 sig figs
|
6. |
Counting numbers and known quantities have unlimited sig figs and are not used in our calculations
Example: 1 day = 24 hours |
Practice ProblemsDetermine the number of significant figures in the following problems.
a. 8.73mm
b. 0.000701 cm c. 200,000 in d. 20,020 mL e. 200,000. in |
Explanation |
Addition/Subtration |
Multiplication/Division |
Round your answer so that is has the same number of decimal places as the least certain number used (Based on sig figs)
|
Round your answer so that it has the same number of significant figures as the number with least number of sig figs
|
Practice ProblemsRound the following example problems using the sig fig math rules
a. 170 mm- 23 mm = 147 mm b. 86.24 cm - 2.3 cm= 83.94 cm c. 121.2 cL x 2.2 cL= 266.42 cL d. 820 g x 2.1 g = 1722 g e. 2.230 m + 2.2 m = 4.430 m |
Explanation |
FUN FACT! |
Significant figures are based off of the instruments used to measure the object. When you read an instrument, you estimate the last digit by reading a measurements one place to the right of the calibration.
|
This ruler would be accurate to the 10ths places and estimated to the 100ths place.
If you were to determine the length of the ruler in mm; an acceptable answer would be either: 10.49 mm, 10.48 mm or 10.47 mm. Using your understanding of how significant figures are determined from an instrument, why are all of the answers acceptable? |