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Unit 1-3 SI units. Do now: read chapter 1.6. How much does it cost?. UNITS MATTER!!. The Nature of Measurement. A Measurement is a quantitative observation consisting of TWO parts. Part 1 - number Part 2 - scale (unit) Examples: 20 grams 6.63 x 10 -34 seconds.
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Unit 1-3 SI units • Do now: read chapter 1.6
How much does it cost? • UNITS MATTER!!
The Nature of Measurement A Measurement is a quantitative observation consisting of TWO parts • Part 1-number • Part 2-scale (unit) Examples: 20grams 6.63 x 10-34seconds
The three major temperature scales. TK = TC + 273.15 TC = TK – 273.15
Temperature scales • Celsius scale • based on freezing and boiling points of water (0 oC – 100 oC) • Kelvin scale • based on absolute zero (0 K) temperature at which particles are at lowest possible energy • NO negative numbers
K = oC + 273 oC = K – 273
Converting Between Celsius & Fahrenheit • TC = (TF – 32)X 5/9 • TF = TC x 9/5 + 32 • You don’t need to memorize the conversion between TCand TF
mega- tera- hecto- deka- giga- kilo- M G k h T da 1012 106 102 101 109 103 deci- d 10-1 centi- c 10-2 milli- m 10-3 micro- 10-6 BASE UNIT --- 100 pico- nano- p n 10-9 10-12 SI Prefix Conversions Prefix Symbol Factor Decimal move left Decimal move right
Prefix conversion g m L 103 10-1 10-2 10-3 102 101 kilo hecto deka Base unit deci centi milli Conversions between prefixes are merely a matter of moving a decimal point. The “base unit” means the you have a quantity (grams, meters, Liters, etc without a prefix.
Metric Conversions g m L 103 10-1 10-2 10-3 102 101 kilo hecto deka Base unit deci centi milli 1 2 3 18 L 18 liters = 18 000 milliliters Example #1: Convert 18 liters to milliliters
Metric Conversions g m L 103 10-1 10-2 10-3 102 101 kilo hecto deka Base unit deci centi milli 3 2 1 450 mg = 0.450 g 450 mg Example #2: Convert 450 milligrams to grams
Metric Conversions g m L 103 10-1 10-2 10-3 102 101 kilo hecto deka Base unit deci centi milli 2 3 1 4 5 6 20 kg 20 kg = 20 000 000 mg Example #3: Convert 20 kilograms to milligrams
Derived SI units • Volume= (length)3 • SI unit of V: m3 • Commonly used units of V: • Liter(L)= dm3 • Milliliter(ml)=cm3
SI Prefix Conversions-concept check a. cm to m b. m3 to L c. ns to s d. kg to g
SI Prefix Conversions-concept check 20 cm = ______________ m 2) 0.032 L = ______________ mL 3) 45 m = ______________ m
Homework • Handout • Due next class.