1. Significant Figures
“SIG FIGS”

2. What are Significant Figures?
In science we say that significant figures are the figures (#’s) in a measurement that consist of all of the numbers known plus one # which is somewhat uncertain or estimated.

3. What measurement is represented in the diagram?
2.35 cm
How many “sig figs”? 3

4. Rules for Sig Figs All non zero numbers are Significant. Ex. 45.87
4 significant figures

5. Numbers with zeros
Zeros appearing between non-zero numbers are significant.
Ex: sig figs
Zeros to the LEFT of a number are NOT SIGNIFICANT. (they are just placeholders)
Ex sig figs
Zeros at the end of a number and to the right of a decimal point are significant.
Ex sig figs

6. Zero rules cont. Zeros at the end of a measurement are questionable.
Ex: sig figs
Ex: 100 ? Ask the source
If there is no decimal at the end assume that the zeros are NOT significant

7. And now for a trick that will blow your mind.
Pacific
Atlantic

8. And now for a trick that will blow your mind.P A

9. If the decimal point is Present…
1. Move in from Pacific side P A

10. If the decimal point is Present…
1. Move in from Pacific side P A
2. Cross out zeros and start counting at the first non-zero number

11. If the decimal point is Present…
1. Move in from Pacific side P A
2. Cross out zeros and start counting at the first non-zero number

12. If the decimal point is Present…
1. Move in from Pacific side P A
2. Cross out zeros and start counting at the first non-zero number
3. Every number after that is significant!!

13. If the decimal point is Present…
1. Move in from Pacific side P
4 sig figs!! A
2. Cross out zeros and start counting at the first non-zero number
3. Every number after that is significant!!

14. If the decimal point is Absent…
1. Move in from the Atlantic side P A
90,000,000 90

15. If the decimal point is Absent…
1. Move in from the Atlantic side P A
90,000,000
2. Cross out zeros and start counting at the first non-zero number 90

16. If the decimal point is Absent…
1. Move in from the Atlantic side P A
90,000,000
2. Cross out zeros and start counting at the first non-zero number 90

17. If the decimal point is Absent…
1. Move in from the Atlantic side P A
90,000,000
2. Cross out zeros and start counting at the first non-zero number 90
3. Every number after that is significant!!

18. If the decimal point is Absent…
1. Move in from the Atlantic side P A
90,000,000
1 sig fig!
2. Cross out zeros and start counting at the first non-zero number 90
3. Every number after that is significant!!