"Goin' like 60" used to be a fanciful or exaggerated way of describing someone or something that was moving very fast. But why was the number 60 chosen for this benchmark? Why not "Goin' like 50" or "70" or "100"? The reason, I think, lies in another phrase that was more commonly understood by our parents and grandparents than it is by our children today: "a mile a minute." Because there are just as many seconds in each minute as there are minutes in each hour - 60 - traveling at a speed of 60 mph means that you are covering each mile in exactly one minute, hence "a mile a minute."
It was during this very week (on Nov. 16) in 1901 that an automobile first achieved the speed of "a mile a minute." A straightaway course was set up at Ocean Parkway in Brooklyn, N.Y., and drivers were timed as they raced across the starting and finishing lines of the measured mile. A man named A.C. Bostwick covered the distance in 56.4 seconds, and later that same day, the record was lowered to 54.6 seconds.Today there are flat, straight, measured-mile courses all across the country. They are known as "interstate highways." The green mile markers that we see along the roadside give us an opportunity to check not only our car's odometer (a word that comes from the Greek "hodos," meaning "road," and "metron," meaning "measure"), but its speedometer (do you see how this word was created?) as well, and to practice some math at the same time.
Children will understand the relationships between distance, time and speed much better if they are actively involved in their calculation. If you hold the speed of your car at a constant 60 mph, while your child times the interval between two-mile markers, the test run should take exactly one minute - you are traveling "a mile a minute." (Any deviation in your results could be caused by error in the distance between markers, error in your speedometer, error in timing the run and other types of error as well.)
The point of "hands on" experiments like this one is to get children to "experience" numbers, measurements and mathematics for themselves. When the phrase "60 miles per hour" begins to live in them as "one mile every minute," and when they see "miles per hour" as saying to them "miles divided by hours," then they will be able to estimate and calculate and understand why any measure of speed (feet per second, kilometers per hour, etc.) is just a measure of distance divided by time.
On my SAT exam, many years ago, there was a math problem that has since become a favorite of mine, one whose solution is made considerably easier by understanding what "a mile a minute" really means. Here it is:
You take your car to a racetrack that measures exactly one mile in circumference. Your goal is to make two complete laps of that track and average exactly 60 mph for the two-mile test. During the first lap, you experience some trouble, and you average only 30 mph for that first mile. Question: What speed must you average over the second lap in order to have your two-lap (that is, two-mile) average come out to exactly 60 mph? This is not a trick question, nor is it a simple problem whose answer is easily apparent. But it's a good problem to ponder - worth the effort, I think - and so I'll give you a week to do just that.- William F. Russell's books for parents and children include "Classics to Read Aloud to Your Children" and "Classic Myths to Read Aloud." Send your questions and comments to him at Family Learning, 2400 E. Main St., Suite 266, St. Charles, IL 60174-2414.