-why do we need to learn this? The Metric System -why do we need to learn this? Metric mishap caused loss of NASA orbiter Orbiter NASA's Climate Orbiter was lost September 23, 1999 By Robin Lloyd CNN Interactive Senior Writer (CNN) -- NASA lost a $125 million Mars orbiter because a Lockheed Martin engineering team used English units of measurement while the agency's team used the more conventional metric system for a key spacecraft operation, according to a review finding released Thursday.

We use the “English” system Units of length The Egyptian cubit, the Indus Valley units of length referred to above and the Mesopotamian cubit were used in the 3rd millennium BC and are the earliest known units used by ancient peoples to measure length. The measures of length used in ancient India included the dhanus (bow), the krosa (cry, or cow-call) and the jojana (stage). The common cubit was the length of the forearm from the elbow to the tip of the middle finger. It was divided into the span of the hand (one-half cubit), the palm or width of the hand (one sixth), and the digit or width of the middle finger (one twenty-fourth) and the span or the length between the tip little finger to the tip of the thumb. The Sacred Cubit, which was a standard cubit enhanced by an extra span—thus 7 spans or 28 digits long—was used in constructing buildings and monuments and in surveying in ancient Egypt; it may have been based on an astronomical measurement.[2] The inch, foot, and yard evolved from these units through a complicated transformation not yet fully understood. Some believe they evolved from cubic measures; others believe they were simple proportions or multiples of the cubit. In whichever case, the Greeks and Romans inherited the foot from the Egyptians. The Roman foot (~296 mm) was divided into both 12 unciae (inches) (~24.7 mm) and 16 digits (~18.5 mm). The Romans also introduced the mille passus (1000 paces) or double steps, the pace being equal to five Roman feet (~1480 mm). The Roman mile of 5000 feet (1480 m) was introduced into England during the occupation. Queen Elizabeth I (reigned from 1558 to 1603) changed, by statute, the mile to 5280 feet (~1609 m) or 8 furlongs, a furlong being 40 rod (unit)s (~201 m) of 5.5 yards (~5.03 m)each. The introduction of the yard (0.9144 m) as a unit of length came later, but its origin is not definitely known. Some believe the origin was the double cubit, others believe that it originated from cubic measure. Whatever its origin, the early yard was divided by the binary method into 2, 4, 8, and 16 parts called the half-yard, span, finger, and nail. The association of the yard with the "gird" or circumference of a person's waist or with the distance from the tip of the nose to the end of the thumb of King Henry I (reigned 1100 - 1135) are probably standardizing actions, since several yards were in use in Britain. There were also Rods, Poles and Perches for measurements of length. The following table lists the equivalents. Length 12 lines = 1 inch 12 inches = 1 foot 3 feet = 1 yard 1760 yards = 1 mile 36 inches = 1 yard 440 yards = quarter mile 880 yards = half mile 100 links = 1 chain 10 chains = 1 furlong 8 furlongs = 1 mile 4 inches = 1 hand 22 yards = 1 chain 5.5 yards = 1 rod, pole or perch 4 poles = 1 chain 40 poles = 1 furlong [edit] Typographical units The point, which is a unit for measuring print type, is recent. It originated with Pierre Simon Fournier in 1737. It was modified and developed by the Didot brothers, Francois Ambroise and Pierre Francois, in 1755. The point was first used in the United States in 1878 by a Chicago type foundry (Marder, Luse, and Company). Since 1886, a point has been exactly 0.3514598 millimeters, or 1/72.27 inch. The pica in any of several related systems measures 12 points. [edit] Units of mass The grain was the earliest unit of mass and is the smallest unit in the apothecary, avoirdupois, Tower, and troy systems. The early unit was a grain of wheat or barleycorn used to weigh the precious metals silver and gold. Larger units preserved in stone standards were developed that were used as both units of mass and of monetary currency. The pound was derived from the mina used by ancient civilizations. A smaller unit was the shekel, and a larger unit was the talent. The magnitude of these units varied from place to place. The Babylonians and Sumerians had a system in which there were 60 shekels in a mina and 60 minas in a talent. The Roman talent consisted of 100 libra (pound) which were smaller in magnitude than the mina. The troy pound (~373.2 g) used in England and the United States for monetary purposes, like the Roman pound, was divided into 12 ounces, but the Roman uncia (ounce) was smaller. The carat is a unit for measuring gemstones that had its origin in the carob seed, which later was standardized at 1/144 ounce and then 0.2 gram. Goods of commerce were originally traded by number or volume. When weighing of goods began, units of mass based on a volume of grain or water were developed. For example, the talent in some places was approximately equal to the mass of one cubic foot of water. Was this a coincidence or by design? The diverse magnitudes of units having the same name, which still appear today in our dry and liquid measures, could have arisen from the various commodities traded. The larger avoirdupois pound for goods of commerce might have been based on volume of water which has a higher bulk density than grain. For example, the Egyptian hon was a volume unit about 11 per cent larger than a cubic palm and corresponded to one mina of water. It was almost identical in volume to the present U.S. pint (~473 mL). The stone, quarter, hundredweight, and ton were larger units of mass used in Britain. Today only the stone continues in customary use for measuring personal body weight. The present stone is 14 pounds (~6.35 kg), but an earlier unit appears to have been 16 pounds (~7.25 kg). The other units were multiples of 2, 8, and 160 times the stone, or 28, 112, and 2240 pounds (~12.7 kg, 50.8 kg, 1016 kg), respectively. The hundredweight was approximately equal to two talents. The ton of 2240 pounds is called the "long ton". The "short ton" is equal to 2000 pounds (~907 kg). A tonne (t) is equal to 1000 kg. [edit] Units of time and angle Hindu units of time on a logarithmic scale. We can trace the division of the circle into 360 degrees and the day into hours, minutes, and seconds to the Babylonians who had sexagesimal system of numbers. The 360 degrees may have been related to a year of 360 days. Many other systems of measurement divided the day differently; other calendars divided the year differently. Please help improve this section by expanding it. Further information might be found on the

English system Only in the USA and Britain Units No systematic approach Based on body parts of the of royalty! And other Imperial connections….. Units Length = Inches (12 inches = length of King’s foot!!!) Mass/Weight = Pounds Volume = Gallons (Queen Anne’s wine gallons!)

Metric or SI System Almost every country except USA and Britain Units Systematic approach Based on 10’s Units Length = Meters Mass/Weight = Grams Volume = Liters Time = Seconds Temperature = celsius

Temperature scale of water Celsius Fahrenheit English system Boiling point 212°F Freezing point 32°F Metric System Boiling point 100°C Freezing point 0°C

Temperature scale Room temp: 25c English system Metric System Body Temp 98.9°F Metric System Body Temp 37°C Room temp: 25c

Some conversion relationships for GRAMS: 1g = 1000 mg can also be written as a fraction: 1000 mg 1 g OR AS : 1 g 1000m g

Example for Unit Conversions 1Km = 1000m 1Km = 100000cm 1Km = 1000000mm 1Km = 1000000000 mm 1m = 100cm 1m = 1000mm 1m = 1000000 mm 1cm = 10mm 1cm = 10000mm 1mm = 1000mm

Practice these conversions Ex. 1: Convert 46.5 mg to grams. 46.5 mg 1 g = 0.0465g 1000 mg

Picket Fence Method for Metric Conversion Problems

Practice these conversions Ex. 1: Convert 125cm to Km. 125 cm 1 m 1Km 0.00125Km 100 cm 1000m

Liters (L) Grams (g) Meters Kilo 1000X Hecto 100x Deka 10x Std unit Deci 1/10 Centi 1/100 Milli 1/1000 Kilometer 1Km= 1000m (abbr. Km) Hectometer 1Hm= 100m (abbr. Hm) Dekameter 1 Dm/dk)= 10m (abbr. Dm) Meters (Abbreviation is m) Decimeter 1dm=0.1m Centimeter 1cm 0.01m Millimeter 1mm= .001m Kilometer 1KL= 1000L (abbr. KL) Hectometer 1HL= 100L (abbr. HL) Dekaliter 1 DL= 10L (abbr. Dm) Liters (L) Deciliter 1dL=0.1L Centiliter 1cL 0.01L Millimeter 1mL= .001L Grams (g) You fill this like the above row! You fill this like the above row!

Homework Help! 11) 1 mL = 0.001L (see previous slide!) 12) 5 cm = 50 mm 13) 10 mg = 0.01 g (1 mg = 0.001 g) 14) 39 m = 39000 mm You figure out the rest!