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# Metric Units A.K.A. (SI) Units

Metric Units A.K.A. (SI) Units. We will study both the American and the Metric systems for the following physical quantities. Length, Weight, and (fluid) Volume. DID YOU KNOW. It’s a metric world

## Metric Units A.K.A. (SI) Units

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1. Metric Units A.K.A. (SI) Units We will study both the American and the Metric systems for the following physical quantities. Length, Weight, and (fluid) Volume

2. DID YOU KNOW It’s a metric world The united states is the only western country not presently using the metric system as its primary system of measurement. The only other countries in the world not using metric system as their primary system of measurement are Yemen, Brunei, and a few small islands; see Fig. 8.15.

3. DID YOU KNOW Lost in space In September 1999, the United States lost the Mars Climate Orbiteras it approached Mars. The loss of the \$125 million spacecraft was due to scientists confusing English units and metric units. The missing Mars Climate Orbiter

4. Length American standard 1 mile = 1760 yards = (5280 feet) 1 yard = 3 feet 1 foot = 12 inches 1 mil = 1/1,000 inch Metric standard 1 kilometer = 1000 meters 1 meter = 10 decimeters 1 decimeter = 10 centimeters ( 1 meter = 100 centimeters) 1 centimeter = 10 millimeters Conversion: 1 inch is defined to be exactly 2.54 cm in July, 1959. (before this, the UK inch measures 2.53998 cm, while the US inch was 2.540005 cm)

5. Do you know? The word “mile” comes from the Latin mille passum, literally “thousand paces,” a unit introduced to Britain by the Roman occupation (57 BCE–450 CE). Each Roman pace is equal to 5 Roman feet, hence there were 5000 Roman feet in a Roman mile. But why does the British mile have grown to 5280 feet? The British has another unit “furlong” for measuring length and area. A furlong has 660 ft and it does not divide into 5000 evenly. So Elisabeth I defined a mile to be 8 furlongs and hence 5280 feet. A furlong is the distance a team of oxen could plow without needing a rest.

6. Historical Note The kilometer was first defined by the French Academy of Science in 1791 as the romantic one ten-thousandth of the length of the meridian through Paris from the North pole to the equator.

7. Weight American Standard 1 ton = 2000 pounds 1 pound = 16 ounces Metric Standard 1 (metric) tonne = 1000 kilograms 1 kilogram = 1000 grams 1 gram = 1000 milligrams Conversion: 1 pound = 0.453 592 37 kilograms hence 1 kilogram  2.2 pounds

8. by the way … The abbreviation for the pound, lb, comes from the Latin libra, meaning “scales”. A dollar bill weighs about 1 gram, a dime weighs about 2 grams, and a quarter 5 grams.

9. by the way … Carat isa unit of mass used for diamonds and other precious stones. The word carat comes from the Greek keration, a carob bean; the seed of a Mediterranean evergreen tree. Traditionally the carat was equal to 4 grains. The definition of the grain differed from one country to another, but typically it was about 50 milligrams and thus the carat was about 200 milligrams. In the U. S. and Britain, the diamond carat was formerly defined by law to be 3.2 troy grains, which is about 207 milligrams. Jewelers everywhere now use a metric carat defined in 1907 to be exactly 200 milligrams or 0.2 gram.

10. Volume for liquid American Standard 1 gallon = 4 quarts 1 quart = 2 pints 1 pint = 16 fluid ounces (also 1 pint = 2 cups 1 cup = 16 Tablespoons 1 TBS = 3 teaspoons ) Metric Standard 1 liter = 1000 milliliters 1 milliliter = 1 c.c. Conversion: 1 gallon = 3.785 411 784 liters  3.8 liters 1 gallon = 231 cubic inches

11. MR. GALLON IS A VISUAL AID TO REMEMBER THE AMOUNTS IN EACH MEASUREMENT.

12. Do you know? Fact: one c.c. of water weighs 1 gram at standard temperature. How much does one gallon of water weigh? Answer: approx. 8.34 lb. How much does one gallon of gasoline weigh? Answer: varies between 5.8 to 6.5 depending on its type

13. Area American Standard 1 square mile = 640 acres 1 acre = 43560 square feet Historical Note An acre is originally defined as the amount of land a pair of oxen could plow in a day. F.Y.I. A football field (including end zones) measures 57600 sq feet, hence it is equal to 1.322 acres, or approximately 1 and ½ acres.

14. Temperature American standard Fahrenheit 32 ºF = freezing 212 ºF = boiling (for pure water) Metric Standard Celsius 0 ºC = freezing 100 ºC = boiling (for pure water) Conversion: F = 1.8 × C + 32 C = (F – 32)/1.8

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