1. Significant Figures

2. True/Accepted Value: 21.00 cm
Group 1
Group 2
Group 3
21.00 cm
21.01 cm
21.02 cm
20.98 cm
21.00 cm
22.00 cm
18.00 cm
23.00 cm
17.50 cm
17.52 cm
17.48 cm
17.45 cm
17.51 cm
Avg
21.00 cm
21.00 cm
17.49 cm
Accurate and
precise
Accurate
not precise
Precise
not accurate

3. Significant Figures
The digits in a measurement that are known with certainty plus the first estimated digit.

4. Determining the # of Sig. Figs
All non-zero digits ARE significant.
Ex) g sig figs
Zeros before non-zero digits are NOT significant
Ex) sig figs

5. Zeros between significant figures ARE significant
Ex) 108 mm sig figs
Zeros after non-zero digits AND after the decimal ARE significant
Ex) 18,1.00 mm sig figs
Zeros after non-zero digits but before the decimal are NOT significant
Ex) sig figs

6. Scientific Notation:
1.810 x 104 mm sig figs
Bar above the significant zero:
18, sig figs

7. Sig Fig Examples – state how many each # has2 82
408.3
9706.2
8.42
234860 4 5 5 6 3 6 9 5

8. 25000
1.26 x 10-5
3.8 x 1020
x 10-7
x 104
x 10-24
0.123
5900
40010 2 3 2 5 5 6 6 3 2 4 7

9. Rules for Sig Fig Calculations
Multiplication and Division
The number of significant figures in the answer is the same as the number with the lowest number of sig figs in the problem.
Ex) 65.01m x 3.4m = m2 (calc)
4 sf sf sf
If you cross off a # in front of the decimal replace it with a zero m2
220 m2

10. Rules for Sig Fig Calculations
Addition and Subtraction
The answer has the same number of places to the right of the decimal as the number in the problem with the smallest number of digits to the right of the decimal.
Ex) 65.01g g = 68.41g (calc)
2 places 1 place 1 place
68.4g