1. BELLRINGER

2. Significant Figures
September 1, 2010

3. Why do we need to learn significant figures?
By the end of today we will be able to identify and apply the rules of sig figs to calculations so that our data is accurate and reported correctly.
TEK 2C TAKS1

4. In General…
When there aren’t zeros at the end or beginning of numbers , ALL numbers are significant
In these slides significant figures will be underlined
Example
12,345 has 5 sig figs
9,876 has 4 sig figs
TEK 2C TAKS1

5. “Zero” Rules
Rule 1
Zeros appearing between non-zero digits ARE significant.
Example
40.7 L has 3 significant figures
87, 009 has 5 significant figures
TEK 2C TAKS1

6. “Zero” Rules
Rule 2
Zeros appearing in front of all nonzero digits are NOT significant
Example
m has 5 significant figures
0.0004kg has 1 significant figure
TEK 2C TAKS1

7. “Zero” Rules
Rule 3
Zeros at the end of a number and to the right of a decimal point ARE significant.
Example
42.00g has 4 significant figures.
mm has 10 significant figures.
TEK 2C TAKS1

8. “Zero” Rules
Rule 4
Zeros at the end of a number when there is NO decimal point, are NOT significant.
Example
2000m has 1 significant figure
 1870 kg has 3 sig figs
TEK 2C TAKS1

9. “Zero” Rules
Rule
Zeros at the end of a number when there IS a decimal point ARE significant
Example
2000.m has 4 significant figures
TEK 2C TAKS1

10. Let’s Check if you Get It…
m has __significant figures.
9280 g has ___ significant figures
1230. g has ___significant figures
has ___ significant figures
TEK 2C TAKS1

11. Which side of the US is the ATLANTIC OCEAN on?
PACIFIC OCEAN
TEK 2C TAKS1

12. The Atlantic Pacific Rule
ATLANTIC OCEAN
PACIFIC OCEAN
If the decimal point is ABSENT:
starting from the very right side of the number,
look for the first non-zero number
count the first non-zero number and every number after that
If the decimal point is PRESENT:
starting from the very left side of the number
look for the first non-zero number
count the first non-zero number and every number after that
24,000

13. Adding/Subtracting with Sig Figs
you can only have an answer to the place value closest to the decimal point of either of the numbers you’re adding/subtracting
Ex g g =
34.987g g = g
BUT you have to round it to the tenths place since 21.2g is only measured to the tenths place
Answer= 51.2g
TEK 2C TAKS1

14. Adding/Subtracting Practice= = =
so  20.7
2.131 so  2.13
so  2
TEK 2C TAKS1