BELLRINGER

Significant Figures September 1, 2010

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

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

“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

“Zero” Rules Rule 2 Zeros appearing in front of all nonzero digits are NOT significant Example 0.019283m has 5 significant figures 0.0004kg has 1 significant figure TEK 2C TAKS1

“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. 9.000000000mm has 10 significant figures. TEK 2C TAKS1

“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

“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

Let’s Check if you Get It… 86.0030m has __significant figures. 9280 g has ___ significant figures 1230. g has ___significant figures 0.00618 has ___ significant figures TEK 2C TAKS1

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

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 0.098076 24,000

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. 34.987g + 21.2g = 34.987g + 21.2g = 56.187g 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

Adding/Subtracting Practice 17.2+ 3.47 = 4.581 - 2.45 = 0.98745 + 0.1 = 20.67 so  20.7 2.131 so  2.13 1.08745 so  2 TEK 2C TAKS1