Our family was numbly watching another night of Olympic coverage on TV when some numbers caught my eye. The event was the women's long jump and as the competitors jumped, the graphics updated their distances: "22 feet, 7¼ inches." Yet when the next woman flew down the track and jumped, the bar behind the sand pit had different numbers: 6, 7, 8. And so, we realized that the network had helped us unit-challenged Americans out and was converting the jump lengths in meters to feet and inches. The announcer who was calling the event went back and forth, however. "She's held on to her spot by a centimeter," he said, and didn't offer a conversion. Is anyone confused?
We had just watched the 100-meter hurdles, 200-meter dash, and the 10-kilometer run. Is the issue that Americans can understand long metric distances but not short ones? Or is the media coverage simply inconsistent in its treatment of units? Most international news sources published the women's long jump result in meters . ESPN hedged its bets and listed the length in feet and inches, followed by the metric length. A quick check of weightlifting results showed most were reported in kilograms while the newsy ESPN story about a dropped barbell listing only pounds (432, to be exact). A pattern emerges. Shot-put results are tabulated in meters, but the stories about the winners and losers are written with both imperial and metric units.
All countries utilize a mixture of historical and metric units, but the United States is especially multicultural in this area. A simple trip to the grocery store might find you purchasing a two-liter container of a soft drink, a gallon of milk and a pound of ground beef. Products are all double labeled, but we are not very good about making conversions. This may not be a problem unless you find yourself spending a significant time in another country that uses the International System of Units (SI), which would be just about any other country in the world. Your first challenge will be finding a place to live. Real estate is listed in square meters. So, is an 80-square-meter property a small apartment, a mansion, or something in between? If you want to buy a fuel-efficient car, can you convert kilometers per liter to miles per gallon? If you brought along a U.S. cookbook and plan to cook in your oven that is calibrated in Celsius or Centigrade degrees, the first thing you'll have to do is make a temperature conversion chart. And if you or your child develop a fever and you call a doctor, you'll need to convert your Fahrenheit-degree temperature to Celsius degrees. Of course, today the answers are as close as your smartphone, because "there's an app for that." Perhaps the most subtle but enduring conversion limitation has to do with air temperature and weather. When the weather forecast in another country calls for a high of 17°C, does that mean you need a coat?
Why is the United States is the only industrialized nation that has not fully accepted the metric system of units in actual practice? Congress's passage of the Metric Conversion Act of 1975 fueled Cold War fears that the U.S. was playing into Communist hands and was largely ignored. The 1988 Omnibus Trade and Competitiveness Act designated the metric system as the official system of units for international trade. So while the U.S. is officially a metric nation, we continue to use other systems of units in various fields and everyday life. This has cost us dearly. While we celebrate this month's landing of the Mars rover, Curiosity, the loss of the 1999 Mars Climate Orbiter has been widely attributed to a metric mix-up.
Chemistry professors teach students to convert a number in one set of units to any other set of units using conversion factors. We also encourage our students to have a feel for English-to-metric conversions that involve everyday things so that they might recognize a miscalculation. Even though today's college freshmen have been learning about the metric system since they were in elementary school, some still struggle with these calculations. Perhaps they've simply watched too much unit-jumbled Olympics coverage.
Follow Cheryl B. Frech on Twitter: www.twitter.com/chemtoo