123 mm = _________ dm 123 mm mm m = 1.23 dm m1 dm 10 XX Day

- A measured digit - scientists repeat experiments and AMOUNT MATTERS!

Significant Figure Rules Rules governing significance: 1. Non-zeros are always Significant (1, 2, 3, 4…). 2. Zeros between non-zeros (sig. figs.) are Always Significant (707). Think Certainty

Significant Figure Rules Rules governing significance: 3. A final zero or trailing zeros in the decimal portion ONLY are significant ( ). 4. Place holders are not significant (0.004, 400) are significant are NOT significant

Significant Figure Rules 4. Place holders are not significant (0.004, 400) Zeroes placed before other digits are not significant; has two significant digits. Zeroes at the end of a non-decimal # are significant only if there is a decimal point (100.). They are NOT sig. if there is not a decimal point (100)

Significant Figure Rules 1.Non-zeros are Always Significant (1, 2, 3, 4…) 2. Zeros between non-zeros are Always Significant (707) Another approach

Left of the decimal Right of the decimal Is the zero by its self Is there a non-zero If yes = Not sig. anywhere to the left If no is there a dec. – if yes = sig. Pt. to the right if yes = Significant Other Zeros Another approach

Left of the decimal Right of the decimal Is the zero by its self Is there a non-zero If yes = Not sig. anywhere to the left If no is there a dec. – if yes = sig. Pt. to the right if yes = Significant Other Zeros Another approach

Significant Figure Practice

HANDOUTS

1.Hand in handout – Conversions Assignment 2.Complete # 74 on page 96 (they must be correct and you must show work) 3.NOTEBOOKS

1. Explain how you convert from Celcius to Kelvins. CP Day Convert 4500 micrograms to milligrams.

1. How many sig. figs.? a b c.0.006

How is certainty expressed in measurements and simple calculations? CP

Rules For Multiplying And Dividing With Sig. Figs. 1. Do the Math – Get an answer 2. Go Back to your original Numbers and Count Significant Figures 3. Use the least # of Significant Figures (from your original #s) For your answer

Rules For Multiplying And Dividing With Sig. Figs * 10 = * 20.0 = = = / 5.5 = …=1.8

Significant Figure Rules To eliminate sig. figs. ROUND To add sig. figs. Use a dec. pt. OR add zeros

Practicing Multiplying And Dividing With Sig. Figs * / 2.5 = 2.0 = 4.0

Significant Figure Rules Practice Assignment Notebook Checks

Day Convert 1,200 km to dm. 2. How many sig. figs.: Calculate with sig figs.: 21.3 * 10.

Significant Figure Rules What are the rules for multiplying and dividing?

Discussion partner review – it’s graded!!!

Rules For Adding And Subtracting With Sig. Figs. 1. Do the Math – Get an answer 2. Go Back to your original Numbers and find the last significant digit (farthest to the right) – underline it in each original number. 3. Find the underlined digit farthest to the left and round your answer to that place

= = 30 = = 4.5 =5 Rules For Adding And Subtracting With Sig. Figs =20.0

= = 61 = 60 Practice Adding And Subtracting With Sig. Figs =

Significant Figure Rules Practice Packet