sand timer puzzle

[levitatingfrog (deleted)]

How does shaking a sand timer side-to-side affect how long it takes to run out? :

[danieldh]

`I would assume you mean an hourglass and the answer to that question can depend on the precise measurements of the apparatus as well as the grade of sand and the speed of movement. Assuming it is standing upright, it is not moved excessively fast, sand still remains in the upper portion, and the sand is reasonably smaller than the opening through which it passes, I would expect it to increase the flow of sand, thus shortening the duration of the timer as shifting it side to side may help clear any blockages that build up at the bottleneck. Larger sand or a smaller opening might cause it to move slower, shaking it excessively hard may halt it until the shaking has stopped as the motion side to side might counteract gravity, and having it lay on its side would prevent any real measurement of time, but would be a tricky thing to throw in.