Eleven and TwelveiStock/Thinkstock
Why not oneteen and twoteen? The reason behind the shift in number naming is that eleven comes from the Germanic term ainlif, which translates to “one left,” or in this case, “one left over” after you count out ten of something. Twelve follows the same rule. It comes from twalif—“two left.” Why we switched from lif to teen (which itself means “ten more than”) for 13 through 19 is something that is sadly lost to antiquity.
2,000 Calories a DayiStock/Thinkstock
This number wasn’t plucked out of thin air—the FDA based this suggestion on science. The average person requires about 2,350 calories a day, according to a U.S. Department of Agriculture survey. But there’s a big caveat: That word average could encourage plenty of people to overeat. Most women need fewer calories than men do, and some older women need as few as 1,600 a day. In establishing the final rule in 1993, the FDA noted that “2,000 calories is easier to use in quick, mental calculations compared to other calorie levels such as 1,900 or 2,350 calories.” So it rounded down to 2,000, a good middle ground for our disparate calorie needs.
911 for Emergency CallsiStock/Thinkstock
Early phone systems didn’t employ phone numbers—the operator had to connect your call manually—and this precluded the real need for a universal emergency code. But when phone numbers became the norm, that changed, and in 1967, a presidential commission urged the creation of a nationwide solution. AT&T, which operated most of the telecoms at the time, chose 911 because it was available and very easy to remember and could be quickly dialed on rotary phones.
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55 Miles Per HouriStock/Thinkstock
What is the reason behind this common speed limit? Gasoline consumption. In 1974, in response to the worldwide oil crisis the year before, Congress and the Nixon administration signed into law the Emergency Highway Energy Conservation Act. Part of the act mandated that highways across the nation have a speed limit of 55 miles per hour in hopes that the lower speed limit would help reduce high levels of fuel consumption. The law was modified in 1987—allowing for some 65 mph zones—and then ultimately repealed in 1995. Despite the change, there is still debate about whether a 55 mph speed limit is safer than a significantly higher one, especially given the steep advances in automotive technology over the years.
ATMs were created in 1967 by a Scottish man named John Shepherd-Barron, who thought that getting cash should be as easy as getting a chocolate bar. But the difficulties lay in ensuring that you were who you said you were. To prevent problems, Shepherd-Barron developed a special type of paper check that acted as a precursor to the debit cards we have today. Each check would cause his cash machine to request a personal identification number—or PIN—that only the account holder knew. Since Shepherd-Barron already had a six-digit ID number he had memorized, given to him by the army, he was going to make the machine require a six-digit PIN from everyone who used it. That likely would have been the standard, but he was overruled … by his wife. She believed that six digits were two too many to remember, and four became the standard.
26.2 Miles in a MarathoniStock/Thinkstock
There’s more to the story than the message delivered by that legendary ancient Greek soldier from the site of a battlefield in Marathon, Greece, to Athens. The modern marathon was born as a flagship event in the first Olympic Games, in 1896, with a distance of approximately 25 miles, targeted to parallel the Marathon-to- Athens mileage. But race organizers for the 1908 Olympic Games in London wanted to add local flair to their course: The race began at scenic Windsor Castle and ended at iconic White City Stadium, with runners finishing only after jaunting around the track toward the royal viewing box. That distance was 26.22 miles, and for the 1924 Games, the organizing body standardized the race length to compare racers over multiple Games. Unfortunately, there were two Games between those years that didn’t use the 26.22-mile standard: In 1912, the race was 24.98 miles, and in 1920, the course was 26.56.
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28 Days in FebruaryiStock/Thinkstock
One of the first Roman calendars (in early BC) did not measure the winter months; it had only 304 days and ten months (March through December), with six months of 30 days and four of 31 days. According to legend, the second king of Rome tacked on an extra two months (January and February) plus 50 days. To make the new months longer (and possibly to honor a Roman superstitious dread of even numbers), he subtracted one day from the 30-day months, leaving 56 total to divide between January and February (or 28 days each). Superstition won the day again, when January was given an extra day for an uneven 29. February, with an even 28 days, was declared a month of “the infernal gods.” And that’s how it became the shortest month.