from the archives …
counterintuitions
A straight, precisely one-mile length of continuous railroad track is laid during a cold night with the two ends firmly fixed in the ground. The next morning the hot sun causes the track to expand by exactly one foot and so the track buckles upward.
What are your initial thoughts?
Is the midpoint of the track raised above the ground by
1) inches
2) feet
3) yards
yards …
51.3834 feet assuming no bending
44.49845 feet exactly with curvature
trivial math but still difficult to believe …
[Number-Crunching, Nahin]