Jenny Castillo Tammy Muller Brandi Stemple. Intro to Physical Science Fall 2010 Dianne Phillips

Transcription

1 Jenny Castillo Tammy Muller Brandi Stemple Intro to Physical Science Fall 2010 Dianne Phillips

2 History of the English System The measurement system commonly used in the United States today is nearly the same that was brought by the colonists from England. These measures had their origins in a variety of cultures Babylonian, Egyptian, Roman, Anglo-Saxon, and Norman French. Roman contributions include the use of 12 as a base number (the foot is divided into 12 inches) and the words from which we derive many of our present measurement unit names. For example, the 12 divisions of the Roman "pes," or foot were called unciae. Our words "inch" and "ounce" are both derived from those Latin words.

3 History of the English System Standardizing various units and combining them into loosely related systems of measurement units sometimes occurred in fascinating ways. Tradition holds that King Henry I decreed that a yard should be the distance from the tip of his nose to the end of his outstretched thumb The length of a furlong (or furrow-long) was established by early Tudor rulers as 220 yards. This led Queen Elizabeth I to declare in the 16th century, that henceforth the traditional Roman mile of 5000 feet would be replaced by one of 5280 feet, making the mile exactly eight furlongs and providing a convenient relationship between the furlong and the mile. Thus, through royal edicts, England by the 18th century had achieved a greater degree of standardization than other European countries. The English units were well suited to commerce and trade because they had been developed and refined to meet commercial needs. Through English colonization and its dominance of world commerce during the 17th, 18th, and l9th centuries, the English system of measurement units became established in many parts of the world, including the American colonies.

4 History of the English System Because of the need for greater uniformity today, standards supplied to all the states by the National Institute of Standards and Technology assure uniformity throughout the country Congress passed the Metric Conversion Act of 1975 to coordinate and plan the increasing use of the metric system in the United States. Efforts of the Metric Board were largely ignored by the American public, and, in 1981, the Board reported to Congress that it lacked the clear Congressional mandate necessary to bring about national conversion. Due to this apparent ineffectiveness, and in an effort to reduce Federal spending, the Metric Board was disestablished in the fall of Congress, recognizing the necessity of the United States conformance with international standards for trade, included new encouragement for U.S. industrial metrication in the Omnibus Trade and Competitiveness Act of 1988 that amended the Metric Conversion Act of 1975 and designates the metric system as the preferred system of weights and measures for United States trade and commerce. Federal agencies were required by this legislation, with certain exceptions, to use the metric system in their procurement, grants and other businessrelated activities by the end of 1992.

5 English System Unit of Weight Unit of Weight Pound basic unit Proportional to mass 3 different systems of weights Avoirdupois System Most widely used Pounds divided into 16 oz Ounce divided into 16 drams Ton = 2,000 lb (short ton) or 2,240 lb (long ton) Grain also used 1 avoirdupois pound = 7,000 grains Great Britain System Stone = 14 lb Troy System Named for Troyes, France where it originated Used only for precious metals Pound is divided into 12 ounces Ounce divided into 20 pennyweights or 480 grains Pound is thus 5,760 grains Grain also used in avoirdupois pound where 1 avoirdupois pound = 7,000 grains Troy Pound is 5,760/7,000 of an avoirdupois pound Apothecaries' weights Based on Troy s weight system In addition to the pound, ounce, and grain, which are equal to the troy units of the same name, other units are the dram (1/8 oz) and the scruple (1/24 oz or 1/3 dram).

6 English System Unit of Length & Units of Length and Area Basic unit is the yard (yd) Area Can be traced back to early Saxon kings. They wore a sash or girdle around the waist that could be removed and used as a convenient measuring device. The word "yard" comes from the Saxon word "gird" meaning the circumference of a person s waist. Fraction of yard is the inch (1/36 yd) and foot (1/3 yd) Commonly used multiples Rod (5 1/2 yd) Furlong (220 yd) Mile (1,760 yd) Acre = 4,840 square yards

7 English System Unit of Liquid Unit of Liquid Measure Basic unit is the gallon Gallon divided into: 4 quarts 8 pints 32 gills Measure US gallon, or wine gallon is 231 cubic inches (cu in) British imperial gallon is the volume of 10 lb of pure water at 62 F and is equal to cu in The British units of liquid capacity are thus about 20% larger than the corresponding American units The U.S. fluid ounce is 1/16 of a U.S. pint the British unit of the same name is 1/20 of an imperial pint and is thus slightly smaller than the U.S. fluid ounce

8 English System Unit of Dry Measure Basic unit is the bushel Divided into 4 pecks, 32 dry quarts, or 64 dry pints The barrel is a unit for measuring the capacity of larger quantities and has various legal definitions depending on the quantity being measured, the most common value being 105 dry quarts.

9 Why should the U.S. Convert to the Metric System? The complexity of converting from one unit to another The differences between American and British units The use of the same name for different units (e.g., ounce for both weight and liquid capacity, quart and pint for both liquid and dry capacity), The existence of three different systems of weights (avoirdupois, troy, and apothecaries')

10 Because of these disadvantages and because of the wide use of the much simpler metric system in most other parts of the world, there have been proposals to do away with the U.S. Customary System and replace it with the metric system The United States is the only country that does NOT use the metric system Some companies from other countries are refusing to purchase products from the U.S. if not labeled in metric units Scientists need a universal way to communicate data (SI Units)

11 History of the Metric System 1585 A decimal system for weights and measures is proposed (by Simon Stevin, in his book "The tenth") Gabriel Mouton, Vicar of St. Paul's Church in Lyons and an astronomer, proposes a metric system. Authorities credit him as the originator of what was to become the metric system Thomas Jefferson proposed a decimal based measurement system for the USA. A subsequent vote in the USA congress to replace the current UKbased system by a metric system was lost by only one vote. 1790s Investigations conducted into reforming French weights and measures, which result in development and adoption of the metric system. Credit for authorizing this is variously assigned (depending on which document one reads) to Louis XVI, Napoleon and the National Assembly of France The metric system becomes the official system of measurement in France

12 History of the Metric System 1840 Metric system compulsory in France since this date. 1800s International support for metric system grows. International scientific community switches to metric system. 1900s By 1900, 39 countries had officially switched to the metric system. By the end of the century virtually all countries, with the USA being the only notable exception, had switched to the metric system UK and USA redefine the inch to be 2.54 cm. In 1963 the UK redefines the pound to be exactly kilograms. In 1985 the UK redefines the gallon to be exactly liters. The USA took similar steps, although the USA gallon is smaller and consequently has been redefined as liters The metric system officially renamed to "Système International d'unités" (International System of Units), and given the official symbol SI. Current The metric system has been adapted by virtually every country, with the only notable exception being the USA (the other non-metric countries are Liberia and Burma). Some countries (such as the UK) are still in transition to the metric system.

13 Most Common Base Units in the Metric System Meter (m) is a unit of length equal to 3.28 feet Gram (g) is a unit of mass equal to approximately pounds (about the mass of a paper clip) Liter (L) is a unit of volume equal to 1.05 quarts. This is much simpler than the American system of measurement, in which we have to remember inches, feet, miles, and many more units of measurement. The metric system is based on powers of 10

14 History of the Metric System The key to the simplicity of the metric system is its use of multiples of 10, and its reliance on only seven different base units. These units can then be combined to make other measures. For example, speed can be expressed as meters per second or volume in terms of cubic meter (a liter is the volume equal to a cube with each side 0.1 meters). In the metric system, the standard units of measurement (see above table) are multiplied by 10 or divided by 10 in order to produce larger or smaller units. For example, a decimeter is a tenth of a meter and a decameter is 10 meters. For even larger or smaller units, one continues to divide or multiple by 10. For example, one can either say '1000 meters' or one can say 'a kilometer', as kilo means '1000' (which is 10 * 10 *10). The following table lists all of the prefixes. Type of measure Standard Unit Symbol length meter m mass (weight) kilogram kg temperature degree Kelvin K (see discussion below) time second s electric current ampere A amount of substance mole mol luminous intensity candela cd

15 The Pre-fixes of Metrics Prefixes plus base units make up the metric system Example: Centi + meter = Centimeter Kilo + liter = Kiloliter Kilo Hecto Deca Base Units Meter Liter Gram Deci Centi Milli

16 Metrics at a Glance Prefix Symbol Value Factor kilo- k 1,000 (thousand) 10 3 hecto- h 100 (hundred) 10 2 deca- da 10 (ten) 10 1 m, L, g 1 (one base unit) 10 0 deci- d 0.1 (tenth) 10-1 centi- c 0.01 (hundredth) 10-2 milli- M (thousandth) 10-3

17 KILO 1000 Units 1 2 HECTO 100 Units Ladder Method DEKA 10 Units 3 Meters Liters Grams DECI 0.1 Unit CENTI 0.01 Unit MILLI Unit How do you use the ladder method? 1 st Determine your starting point. 2 nd Count the jumps to your ending point. 4 km = m Starting Point Ending Point How many jumps does it take? 3 rd Move the decimal the same number of jumps in the same direction = 4000 m

18 Conversion Practice Try these conversions using the ladder method mg = g 1 L = ml 160 cm = mm 14 km = m 109 g = kg 250 m = km Compare using <, >, or =. 56 cm 6 m 7 g 698 mg

19 From Standard/US to SI/Metric Units Symbol When You Know Multiply By To Find Symbol LENGTH in inches 25.4 millimeters mm ft feet meters m yd yard meters m mi miles 1.61 kilometers km AREA in 2 square inches square millimeters mm 2 ft 2 square feet square meters m 2 yd 2 square yards square meters m 2 ac acres hectares ha mi 2 square miles 2.59 square kilometers km 2

20 From Standard/US to SI/Metric Units Symbol When You Know Multiply By To Find Symbol VOLUME fl oz fluid ounces milliliters ml gal gallons liters L ft 3 cubic feet cubic meters m 3 yd 3 cubic yards cubic meters m 3 MASS oz ounces grams g lb pounds kilograms kg T short tons (2000 lb) megagrams (or "metric ton") TEMPERATURE o F Fahrenheit (F-32) x 5 / 9 or (F-32) / 1.8 Celsius Mg (or "t") o C

21 From SI/Metric to Standard/US Units Symbol When You Know Multiply By To Find Symbol LENGTH mm millimeters inches in m meters 3.28 feet ft m meters 1.09 yards yd km kilometers miles mi AREA mm 2 millimeters square inches in 2 m 2 square meters square feet ft 2 m 2 square meters square yards yd 2 ha hectares 2.47 acres ac km 2 square kilometers square miles mi 2

22 From SI/Metric to Standard/US Units Symbol When You Know Multiply By To Find Symbol VOLUME ml milliliters fluid ounces fl oz L liters gallons gal m 3 cubic meters cubic feet ft 3 m 3 cubic meters cubic yards yd 3 MASS g grams ounces oz kg kilograms pounds lb Mg (or "t") megagrams (or "metric ton") short tons (2000 lb) TEMPERATURE o C Celsius 1.8C + 32 Fahrenheit o F T

23 References a.pdf WEIGHTSandMEASURES/MetricHistory.html chart.html WEIGHTSandMEASURES/MetricHistory.html