9/27/20131Mon, Sept 30• Lecture 2 (Communication )– Scientific Notation (2.1)– Units and Measurements of Length, Volume, and Mass (2.2‐3)• Questions we’ll answer:– Why does it matter how we communicate science? – How do we know what kind of measurement we’re presented with?– How do we appropriately and efficiently communicate a measurement?The “Gimli Glider”Measurements and Units• All physical measurements are comprised of a number and a unit. • The unit tells you what kind of measurement was made: length, volume, mass, time, temperature, etc.• NO MEASUREMENT IS COMPLETE WITHOUT UNITS!!!• There are many systems of units. In science, we typically use the metric or the SI (International System) system of units because they are based on the decimal system. Measurement Metric SI Other UnitsLength meter (m) meter (m) foot (ft), inch (in)Volume liter (L) cubic meter (m3) gallon (gal), ounce (oz)Mass gram (g) kilogram (kg) pound (lb), ounce (oz)Time second (s) second (s) hour (hr), minute (min)Temperature Celsius (C) Kelvin (K) Fahrenheit (oF) 9/27/20132Scientific Notation• A convenient way of expressing very large or very small numbers in terms of “powers of 10.”• A power of 10 is commonly referred to as an “order of magnitude.” These numbers are the same order of magnitude: 10xN where = a number between 1 and 10 = exponent..."power" of 10 Nx6,000,000 60022 100.06 0.000000006 28.09 10= 6 10 102= 6 10= 6 100 = 6 1,000,000= 6 10 10 10 10 10 10 6= 6 1021 = 6 102= 6 106= 1006= 1,000,000,00091= 6 109= 6 10Converting a Number to Sci. Notation1. Move the decimal point to the right or left to get a coefficient that is between 1 and 10.2. Count the spaces you moved the decimal place…this becomes the exponent on 10.a) If the number is greater than 1, the exponent is positive.b) If the number is less than 1, the exponent is negative.3.4928.302 33.492 10218.302 1028.302 10 10001 100Example 1: Write 3,492 in scientific notation.Example 2: Write 0.08302 in scientific notation.9/27/20133Scientific Notation ExamplesConvert the following to scientific notation: 123,876.3 0.000238 9100Convert the following to standard format: 3.6 x 10–5 2.12 x 105 6.49 x 100In the following pairs, choose the larger number: 4.9 x 10–3or 5.5 x 10–9 1250 or 3.4 x 102 0.000 000 004 or 5 x 10–8Prefixes Used in the SI System• Scientific notation is one way to make the communication of very large or very small numbers more manageable.• Unit prefixes are another handy method of communicating the order of magnitude of a measurement.Know these prefixes!!9/27/20134Metric Unit Prefixes and Equalities• Metric units are based on powers of 10.• A metric unit name consists of a base unit and a pre fix to indicate the power of 10.• Examples:1 unit =kilo 100 0 unitsmega 1,000,01 unit = u00 nits1 unit 1centi1= 00unit1 unit =1milli10 00unit3= 10 units6= 10 units2= t10 uni3= t10 uni• Complete the following metric relationships:1 kg = ______ g1 g = ______ g1 nL = ______ L1 L = ______ dL1 cm = ______ m1 Mm = ______ m• In the following pairs, which is the smaller unit?kg or ngm or mmkg or mg9/27/20135• Rewrite the following measurements with an SI pre fix so that the result is between 1 and 1000.38.09 10 m55.6 10 g84.75 10