Sig Fig Rules 1) All non-zero digits are significant 2) All zeroes between significant digits are themselves significant. 3) All digits of any* number containing a decimal are significant. 4) Exception to number 3: For any numbers less than 1 (i.e., decimal numbers or fractions) zeroes between the decimal point and the first non-zero number are NOT significant. 5) For numbers greater than 1 trailing zeros are not significant unless the number contains a decimal (rule 3).

Practice 726  ______ s.f. (Rule #1) 3608  ______ s.f. (Rule #2) 230.  ______ s.f. (Rule #3, this is BAD form!) 230.0  ______ s.f. (Rule #3) 45.08  ______ s.f. (Rule #3) 670.003  ______ s.f. (Rule #3)

More practice 0.0024  ______ s.f. (Rule #4) 5.11 x 10-4  ______ s.f. (Rule #4) 2.600 x 10-8  ______ s.f. (Rule #4 & #3) 3,100,000  ______ s.f. (Rule #5) 3,100,000.000  ______ s.f. (Rule #5 & #3) 4.56 x 1016  ______ s.f. (Rule #5) 2.90 x 104  ______ s.f. (Rule #5 & #3)* If a number is expressed in sci. not. It is generally assumed that ALL the digits to the left of the multiplication sign are significant. This is essentially rule #3.

T G M k base m µ n p f C What this chart means: For big things: Terra Giga Mega kilo milli micro nano pico fempto T G M k base m µ n p f 1012 109 106 103 10-3 10-6 10-9 10-12 10-15 centi C 10-2 What this chart means: For big things: 1 Terrameter = 1012 Meters OR 10-12 Terrameters = 1meter For little things: 1 micrometer = 10-6 Meters OR 106 micrometers = 1meter

Making conversions Step 1: Write down a conversion factor between the two types of things you are comparing. If you don’t know it, look it up.* Step 2: Use “railroad tracks” or “factor-label” method to set up conversion formula. If you need to make multiple conversions, set each one up one at a time. Step 3: Multiply across the top, multiply across the bottom, divide top by bottom. Answer. Include any units remaining that did not cancel. *You will need to know your metric prefixes and their values for the exam & the rest of the year!

Practice 240 Mm = __________ m 736 nm = ___________ m 1 Mm = 106 m Ans: 7.36 x 10-7 m

More practice 6.42 m = ___________ km 42 m = ___________ µm Ans: 6.42 x 10-3 km Ans: 4.2 x 107 µm

Still more practice (the “hard” ones) 12.3 Gm = _____________ pm 60,000 fm = _____________ km 1 Gm = 109 m 1 m = 1012 pm 1 fm = 10-15 m 1000 m = 1 km Ans: 6 x 10-14 km

Weird, multi-dimensional conversions PreAP packet number 8 on dim. analysis wrksht. 12 mi/hr*s = ___________ m/s2 1 mile = 1609 meters 1 hr = 3600 seconds

PreAP Students: If you don’t know the conversion factor look it up: In a book On the internet (wikipedia is good) On a website: http://www.onlineconversion.com “MultiConvert” app for smartphone If you use the website or the app: don’t cheat. Don’t go straight to the result, even if you can. This does you no good on your upcoming test or in general. Just use it to find the conversion factors. You could also use it to check your work