1. Significant Figures

2. Significant figures are the digits in any measurement that are known with certainty plus one digit that is uncertain. Number of significant figures = All certain digits + One uncertain digit

4. Determine the number of significant figures in each of the following measurements: 1. 14.386 Rule #1 All non-zero digits are significant. 5 sig. fig. 2. 0.0078 Rule #4 Trailing zeros at the end of a number are significant only if the number (a) contains a decimal point or (b) contains an overbar. Rule #2 Zeros to the left of the first non-zero digit are not significant. Rule #3 Zeros between non-zero digits are significant. 3. 5.0078 4. 65.00 2 sig. fig. 5 sig. fig. 4 sig. fig.

5. 1. 36 000 Rule #4 Trailing zeros at the end of a number are significant only if the number (a) contains a decimal point or (b) contains an overbar. 5 sig. fig. 2. 7 800 Rule #3 Zeros between non-zero digits are significant. Rule #4 Trailing zeros at the end of a number are significant only if the number (a) contains a decimal point or (b) contains an overbar. Rule #2 Zeros to the left of the first non-zero digit are not significant. 3. 0.00069 4. 30008 2 sig. fig. 5 sig. fig.

6. More Practice Problems Determine the number of significant figures in each of the following measurements: a) 5 000 Rule #4 Trailing zeros at the end of a number are significant only if the number (a) contains a decimal point or (b) contains an overbar. 1 sig. fig. b) 3005 Rule #2 Zeros to the left of the first non-zero digit are not significant. Rule #1 All non-zero digits are significant. Rule #2 Zeros to the left of the first non-zero digit are not significant. c) 0.000002 d) 0.00050 4 sig. fig. 1 sig. fig. 2 sig. fig.

7. e) 7 698 Rule #1 All non-zero digits are significant. 4 sig. fig. f) 76 980 Rule #2 Zeros to the left of the first non-zero digit are not significant. Rule #4 Trailing zeros at the end of a number are significant only if the number (a) contains a decimal point or (b) contains an overbar. Rule #2 Zeros to the left of the first non-zero digit are not significant. Rule #4 g) 0.50 h) 70 4 sig. fig. 2 sig. fig.