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  1. 1. Units of Measurement Why they are important...
  2. 2. ....like $125,000,000 important! In 1999 NASA’s $125,000,000 Mars Climate Orbiter space probe entered the Martian atmosphere burst into flames and crash landed. It was entirely destroyed.
  3. 3. A committee was formed to investigate the crash.
  4. 4. They found that... ...the crash stemmed from a miscommunication between the probes manufacturer and the navigational team regarding units... oLockheed Martin used English Units (inches, feet, pounds) oThe Navigation Team used Metric Units (Meters, Newtons)
  5. 5. “This is going to be the cautionary tale that will be embedded into introduction to the metric system in elementary school, high school, and college science courses till the end of time.”
  6. 6. English Standard Units • You are probably familiar with these, they include: • Inches • Feet • Yard • Mile • Pounds • Cup
  7. 7. What’s the problem? The USA is the only major country in the world that still uses English Standard Units.
  8. 8. The Metric System • The rest of the world uses it. • In the United States the Metric System is used by: • Scientists • Doctors • Engineers • Anyone who works with international clients • Basically metric units are used for everything except day-to-day life in America. • Also known as SI or Systeme Internationale Units
  9. 9. The Metric System Is Easy! • The Metric System is based upon Powers of 10. – 1000 Millimeters in 1 Meter – 10 Millimeters in 1 Centimeter – 100 Centimeters in 1 Meter – 1000 Meters in 1 Kilometer
  10. 10. But what about English Standard units? • Unlike Metric units English Standard units are based on complete randomness. – They are so strange they probably weren’t even developed by a scientist but rather a creepy guy in a van. Not really but it was way funnier that way!
  11. 11. Seriously though, you’ll like the metric system if you give it a chance!
  12. 12. Base Units • The metric system uses certain fundamental Base Units: • Length = Meters • Mass = Kilogram • Volume = Liter • Time = Second • Temperature = Degrees Kelvin
  13. 13. Metric Units Time: Unit Seconds: defined as time for a certain excited atom (cesium) to make a specified number of oscillations. Length: Unit Meters: defined as distance light travels in a specified fraction of a second.
  14. 14. Metric Units One cubic meter is 1,000 liters. One cubic meter of water has a mass of 1,000 kg, one metric ton, about 2,200 lbs. Mass: Unit Kilogram: defined as the mass of a chunk of platinum in Paris, shown here. Volume: Unit Liter: defined as the mass of 1 Kilogram of water.
  15. 15. Metric Prefixes If you need a larger or smaller unit, one can be created by adding a prefix.
  16. 16. Learning Check A rattlesnake is 2.44 m long. How long is the snake in cm? a) 2440 cm b) 244 cm c) 24.4 cm
  17. 17. English and SI Conversions • If you know ONE conversion for each type of measurement, you can convert anything! • You must memorize and use these conversions: –Mass: 454 grams = 1 pound –Length: 2.54 cm = 1 inch –Volume: 0.946 L = 1 quart
  18. 18. Learning Check A rider on RAGBRAI averages 18 miles per hour what is their speed in kilometers per hour?