Is it possible to make an hourglass that measures different amounts of time in one direction than the other? Say, 25 minutes right-side up, and 5 minutes upside down, for pomodoros. Moving parts are okay (flaps that close by gravity or something) but it should not take additional effort to flip.
I don’t see why this wouldn’t be possible? It seems pretty straightforward to me; the only hard part would be the thing that seems hard about making any hourglass, which is getting it to take the right amount of time, but that’s a problem hourglass manufacturers have already solved. It’s just a valve that doesn’t close all the way:
Unless you meant, “how can I make such an hourglass myself, out of things I have at home?” in which case, idk bro.
One question I have about both your solution and mine is how easy it is to vary the time drastically by changing the size of the hole. My intuition says that too large holes behave much differently than smaller holes and if you want a drastic 5x difference in speed you might get into this “too large and the sand sort of just rushes through” behavior.
While I’m sure there’s a mechanical solution, my preferred solution (in terms of implementation time) would be to simply buy two hourglasses—one that measures 25 minutes and one that measures 5 minutes—and alternate between them.
First thought is to have two separate holes of slightly different sizes, each one blocked by a little angled platform from one direction. I am not at all confident you could get this to work in practice
Is it possible to make an hourglass that measures different amounts of time in one direction than the other? Say, 25 minutes right-side up, and 5 minutes upside down, for pomodoros. Moving parts are okay (flaps that close by gravity or something) but it should not take additional effort to flip.
I don’t see why this wouldn’t be possible? It seems pretty straightforward to me; the only hard part would be the thing that seems hard about making any hourglass, which is getting it to take the right amount of time, but that’s a problem hourglass manufacturers have already solved. It’s just a valve that doesn’t close all the way:
Unless you meant, “how can I make such an hourglass myself, out of things I have at home?” in which case, idk bro.
One question I have about both your solution and mine is how easy it is to vary the time drastically by changing the size of the hole. My intuition says that too large holes behave much differently than smaller holes and if you want a drastic 5x difference in speed you might get into this “too large and the sand sort of just rushes through” behavior.
While I’m sure there’s a mechanical solution, my preferred solution (in terms of implementation time) would be to simply buy two hourglasses—one that measures 25 minutes and one that measures 5 minutes—and alternate between them.
Or just bundle them together like this: https://www.amazon.de/Bredemeijer-B0011-Classic-Teatimer-Edelstahl/dp/B00SN5U5E0/
First thought is to have two separate holes of slightly different sizes, each one blocked by a little angled platform from one direction. I am not at all confident you could get this to work in practice