1. SIGNIFICANT FIGURES

2. Significant Figures Significant Figures ( SigFigs)
Measured digits in a reported number.
More SigFigs = more confidence
Less SigFigs = less confidence
A Laboratory instrument is read as far it can be, and the last number is estimated.
There are Limitations to how confident you can be!
Compare 2m vs m
Which one seems more confident?

3. What is the correct mass to report?
Measured Mass is _______________

4. What is the correct mass to report?
Measured Mass is g
OR g

5. Rules for recognizing SigFigs: When a number has a decimal:
Significant Figures
Rules for recognizing SigFigs:
When a number has a decimal:
Read Left to Right until you
Reach the first nonzero number
Then you begin counting SigFigs
Until you run out of digits (including any zeros along the way)
Example: g = _______ SigFigs?

6. Significant Figures Practice: 82.700 K ____sig figs
J ____sig figs
3.034 g ____sig figs
3.220 x 105 m ____sig figs

7. Significant Figures
Rules for recognizing SigFigs:
When a number has no decimal:
Read Right to Left until you
Reach the first nonzero number
Then you begin counting SigFigs
Until you run out of digits (including any zeros along the way)
Example: m = _______ SigFigs?

8. Significant Figures Practice: 421 m ____ sig figs
800,890 J ____sig figs
39,059,000 g ____sig figs
523,000 L ____sig figs

9. Significant Figures
Counted Quantites and Constants have absolute values & we don’t count SigFigs
Either you counted the number of items right, or you didn’t!
Example:
14 bananas

10. Significant Figures
How many significant figures are in each of the following numbers?
5.40 ng ____
Amp ____
1.2 x 103 mt ____
1,000 BTU ____
210 N ____
9.010 x 10-6  dm ____
mL ____
D ____
801.5 K ____
2,370.0 Cal ____

11. Significant Figures
Why are significant figures important when taking data in the laboratory?
When you measure something, you never get 100% accuracy on its measurement, so you need a way to show just how accurate it is.

12. Significant Figures
Why are significant figures NOT important when solving problems in your math class?
In math, we assume that all numbers are either 100% accurate, or that they are constants, and thus have no uncertainty or error involved in their creation.

13. Significant Figures
Using two different instruments, I measured the length of my foot to be 27 centimeters and centimeters. Explain the difference between these two measurements.
The second measurement was made with a ruler that had more graduations, giving a higher level of certainty and more Significant Figures

14. Signficant Figures and Math
We will be required to do math with our SigFigs
Two rule sets cover this:
Addition/Subtraction
And
Multiplication/Division

15. Addition and Subtraction Sig Fig Rules
line up the decimals
draw a line to the right of the number with the least precision (shortest column)
answer can’t go past the line
use the 1st digit past the line to determine where to round off
Example:
32.00 m m m = ????

16. Addition and Subtraction Sig Fig Rules
line up the decimals
draw a line to the right of the number with the least precision (shortest column)
answer can’t go past the line
use the 1st digit past the line to determine where to round off
Example:
32.00 m m m = ???? m m
+____________ m m
Must round to:
262.3 m

17. Addition and Subtraction Sig Fig Rules
210.6 mm mm = ____________
cm cm =____________
m m =____________
84000 cm cm =____________
92008 g g =____________
8.000 mm m =____________
84.34 g g =____________
9.81 cm cm =____________
n n =____________

18. Multiplying and Dividing Sig Fig Rules
Answer can have no more SigFigs than the factor with the fewest number of SigFigs.
This means that constants and quantities do not affect sigfigs in the answer!
Example: x 42 = ???

19. Multiplying and Dividing Sig Fig Rules
500 kg X 32 kg =____________
680.0 n X 100. n =____________
g X 1000 g =____________
4560 m X m =____________
85 kg X kg =____________
9200 L ÷ 873 L =____________
kg2 ÷ 62 kg =____________
985 g2 ÷ 500. g =____________
10000 n2 ÷ 0.10 n =____________
g2 ÷ 25 g=____________