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# Appropriate Measurement Tools

## Choose among rulers, tape measures, yard sticks, and meter sticks for given situations.

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Practice Appropriate Measurement Tools
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Bridging the Gap

Credit: John Benson
Source: http://www.flickr.com/photos/j_benson/1490494986

Have you ever heard the expression “as the crow flies”? This idiom is used when engineers measure a road distance in a direct line without any detours. Most recently, this phrase was involved in an argument over how to measure the world’s longest bridge, the Jiaozhou Bay Bridge in China.

#### News You Can Use

Until the Jiaozhou Bay Bridge was completed in June 2011, the Lake Pontchartrain Causeway in Louisiana was considered to be the world’s longest bridge over open water, with a length of nearly 24 miles. However, upon its completion, the 26.3-mile-long Jiaozhou Bay Bridge was deemed the world’s longest bridge by The Guinness Book of World Records—and that’s when the argument started! Because the Jiaozhou Bay Bridge is curved, while the Lake Pontchartrain Causeway is straight, Louisiana claimed that its bridge was technically longer once this fact was taken into consideration! And indeed, the total over-water length of the Jiaozhou Bay Bridge—“as the crow flies”—is just 16 miles.

Credit: Dr. Bernd Gross
Source: http://commons.wikimedia.org/wiki/File:Jiaozhou-Bay-Bridge.jpg

The expression “as the crow flies” can be thought of as a measurement tool. Though it isn’t a ruler or a yardstick or an odometer, it refers to the measurement of the direct, point-to-point aerial path that might be taken by a crow. Because The Guinness Book of World Records uses a different method of measurement—namely, the distance that would be covered by the structure if its curve were straightened out—for now, the Jiaozhou Bay Bridge holds the title of the world’s longest bridge.

#### Explore More

Learn more about finding distances “as the crow flies” at the first link below. You can use the second link to calculate distances between any two cities in the world.

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