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THE METRIC SYSTEM!! The universal language of science What is the difference between metric and standard (English) System of measure? The English system uses a base of 12 The Metric system uses a base of 10 Why does the United States still use the English system? Convenience? Maybe we just don’t want to change because we would have to learn some new stuff Cost? It would cost a lot of money: Think about roadsigns, containers, cars, foods, etc Probably a little of both… OK…Here we go This is a much easier way to do calculations, and make conversions: Try these 2 calculations one in the English system and one in metric Convert 7,899 inches to miles Convert 7,899 centimeters into kilometers First the English measure 7,899 inches/12inches in a foot 658.25 feet • 658.25 feet/5,280 feet in a mile .12466856060 of a mile • All that just to make 2 conversions???? Now the Metric method 7,899 centimeters to kilometers… Ready? Go… Move the decimal 5 places to the left. That’s it. .07899 kilometers Start with base units Base units are what we multiply by the prefix to arrive at a new quantity. It doesn’t matter what it is…just apply the prefix to the base unit. Here are some common base units Mass=grams Grams-How much is a gram? About a penny. Volume 2 ways to do this Liters-usually liquid or gas containers Meters cubed: B X H X W = M3 Length=meters Meters: The length of a guitar is roughly one meter. Temperature Celsius, or Centigrade: How do you covert Farenheit to Celsius? 98.6F is roughly equal to 37C Prefixes Now that we have the base units, we need to know what to do with them. In the metric system, we add a prefix to a base and multiply the number represented by the prefix by one base unit… Here we go Prefix names and numeric meanings Here are some fun ones Yotta000 Zetta Exa Peta Tera Giga Mega- Y 10 24 1 000 000 000 000 000 000 000 Z E P T G M 10 21 10 18 10 15 10 12 10 9 10 6 1 000 000 000 000 000 000 000 1 000 000 000 000 000 000 1 000 000 000 000 000 1 000 000 000 000 1 000 000 000 1 000 000 More useful prefixes kilohectodekaUnit decicentimillimicronano- k h D ? d c m mu n 10 3 10 2 101 100 10 -1 10 -2 10 -3 10 -6 10 -9 1000 100 10 1 0.1 0.01 0.001 0.000 001 0.000 000 001 Putting it together Add the prefix to the base: Example how many grams is 25 kG Kilo is 1000 25 is 25 (duh) So this is 25,000 grams Conversions Since everything is base 10, all you have to do is move the decimal: Convert 3899 mL to L Look at the prefix scale and move the decimal the same direction as the prefix Since we are moving from milli to unit, move the decimal 3 spaces to the left: 3.899 L Practice 1) 2) 3) Convert 23 mg to dg 45 DL to mL 9966 mm to km kilo- k hecto- h deka- D Unit ? deci- d centi- c milli- m micro- mu 001 nano- n 000 001 Going up=decimal to the left Going down=decimal to the right 10 3 10 2 101 100 10 -1 10 -2 10 -3 10 -6 1000 100 10 1 0.1 0.01 0.001 0.000 10 -9 0.000 Answers 1) 23 mg = .23 dg 2) 45 DL = 450000 mL 3) 9966 mm = .009966 km Celsius In Science and really in the rest of the world we use the Celsius scale, named after Anders Celsius (1701-1744). This is based on: freezing = 0 degrees C boiling = 100 degrees C… Unfortunately these temperatures can be expressed as negatives which makes them difficult to do calculations with, sooooo…… Kelvin Scale The Kelvin scale is more useful in science because there are no negative temperatures. This is based on the absolute zero concept. That is the temperature at which all molecular motion stops. This is 273.15 below zero Celsius. That is cold!!! This is about 460 degrees below zero Farenheit