Significant Figures “SIG FIGS”

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.

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

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

Numbers with zeros Zeros appearing between non-zero numbers are significant. Ex: 7089 4 sig figs Zeros to the LEFT of a number are NOT SIGNIFICANT. (they are just placeholders) Ex. 0.000378 3 sig figs Zeros at the end of a number and to the right of a decimal point are significant. Ex. 7.500 4 sig figs

Zero rules cont. Zeros at the end of a measurement are questionable. Ex: 100. 3 sig figs Ex: 100 ? Ask the source If there is no decimal at the end assume that the zeros are NOT significant

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

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

If the decimal point is Present… 1. Move in from Pacific side P A 0.004000

If the decimal point is Present… 1. Move in from Pacific side P A 0.004000 2. Cross out zeros and start counting at the first non-zero number

If the decimal point is Present… 1. Move in from Pacific side P A 0.004000 2. Cross out zeros and start counting at the first non-zero number

If the decimal point is Present… 1. Move in from Pacific side P A 0.004000 2. Cross out zeros and start counting at the first non-zero number 3. Every number after that is significant!!

If the decimal point is Present… 1. Move in from Pacific side P 4 sig figs!! A 0.004000 2. Cross out zeros and start counting at the first non-zero number 3. Every number after that is significant!!

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

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

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

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!!

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!!