Drop the sneaker out the highest window of a tall building (ensure no pedestrians could be hit, of course).  Get in the elevator and head back to the ground floor.  Note that the square root of 1 is 1, the square root of 4 is 2, and 2 is a third of the way between 1 and 4, so square root of 2 is approximately 1 1/3.  Go outside to see what happens to a sneaker dropped from that height.  Keep the stopwatch, stopwatches are cool.