UNITS Science makes all measurements using the metric system LengthMeter (m) MassGram (g) VolumeLiter(L) ( = inches) ( = ounces) ( = quarts) EX1-1 (of 19)

METRIC PREFIXES PrefixSymbolBase Unit Multiplying Factor gigaG 10 9 megaM10 6 kilok10 3 BASE UNIT byte= bytes 1 m = m 1 g = g EX1-2 (of 19)

METRIC PREFIXES PrefixSymbolBase Unit Multiplying Factor gigaG 10 9 megaM10 6 kilok10 3 BASE UNIT10 0 decid10 -1 centic10 -2 millim10 -3 microμ10 -6 nanon10 -9 EX1-3 (of 19)

Convert 525 meters into kilometers An EQUALITY STATEMENT between meters and kilometers is needed 1 km = 10 3 m An equality statement can be written as a fraction called a CONVERSION FACTOR 525 m= km 10 3 m _______ 1 km _______ 10 3 m or x 1 km ________ 10 3 m EX1-4 (of 19)

Convert grams into centigrams 1 cg = g g= 17.0 cgx 1 cg ________ g Convert 24.5 milliliters into liters EX1-5 (of 19) L

Convert decimeters into micrometers 1 dm = m 1 μm = m dm= 67,400 μm x m ________ 1 dm x 1 μm ________ m EX1-6 (of 19)

Convert 22.5 mL/s into L/min 1 mL = L 1 min = 60 s 22.5 mL ___________ s = 1.35 L/minx L ________ 1 mL x 60 s ________ 1 min EX1-7 (of 19)

Convert J/hr into kJ/day kJ/day EX1-8 (of 19)

SIGNIFICANT FIGURES Every digit recorded in a measurement (all certain digits plus one uncertain digit) LABORATORY MEASUREMENTS All measurements indicate the (1)magnitude of the measured property (2)accuracy of the measured property EX1-9 (of 19) Measurements display all digits known for sure, plus one estimated digit

Significant figures are determined only for measurements, not for (1)Counted numbers (28 students enrolled) (2)Defined numbers (1 km = 10 3 m) EX1-10 (of 19)

RULES FOR COUNTING SIGNIFICANT FIGURES (1)All nonzero digits are significant (2)Zeros that start a number are not significant EX1-11 (of 19) 596     0.001

RULES FOR COUNTING SIGNIFICANT FIGURES (3)Zeros that end a number without a decimal point are not significant 3002, EX1-12 (of 19)

A non-significant zero can be made significant with a bar over it _ 300 _ EX1-13 (of 19) 300    1300  0.1

,01943,100 1, EX1-14 (of 19)

When writing a measurement in scientific notation, only significant figures are shown _ × × × 10 2 EX1-15 (of 19)

ADDING AND SUBTRACTING MEASUREMENTS The answer’s last digit will be in the same place as the last digit in the least accurate measurement 20.63mL + 6.6mL Hundredths is the last sig fig Tenths is the last sig fig 27.23mL 27.2mL Tenths must be the last sig fig ← Correct answer EX1-16 (of 19)

ADDING AND SUBTRACTING MEASUREMENTS The answer’s last digit will be in the same place as the last digit in the least accurate measurement 1,840km + 576km Tens is the last sig fig Ones is the last sig fig 2,416km 2,420km Tens must be the last sig fig ← Correct answer EX1-17 (of 19)

MULTIPLYING AND DIVIDING MEASUREMENTS The number of sig fig’s in the answer will equal the number of sig fig’s in the factor with the least number of sig fig’s (2.41 m)(0.25 m) Sig Fig’s:32Answer will have 2 sig fig’s = m 2 = 0.60 m 2 ← Correct answer EX1-18 (of 19)

MULTIPLYING AND DIVIDING MEASUREMENTS The number of sig fig’s in the answer will equal the number of sig fig’s in the factor with the least number of sig fig’s m ÷ 0.50 s Sig Fig’s:42Answer will have 2 sig fig’s = m/s = 1200 m/s ← Correct answer EX1-19 (of 19)