Hourglass Operation

This poll is inspired by the Wizard's "Hourglass puzzle"

In all the movies I've seen where time running out of an hourglass was an important plot point, it seemed the hero always had until the last grain of sand hit the pile in the bottom bulb, to save the day. However, I assume the height of the pile at the bottom of the glass could vary quite a bit, so it seems more accurate to mark the end of the measurement as the moment when the last grain of sand leaves the top bulb.

What event marks the end of the measured period when using an hourglass?

I said "Other"

Just how concerned with exact time measurments are you, if you're using an hourglass?

That said, the difference in time between when the last grain leaves the top bulb, and when it hits the pile is insignificant enough to make the two choices equal. And then you throw in a "halfway" choice? C'mon!

I would also vote for "other". Schrodinger shows that simply by observing the hourglass, you have no idea when the end of the time period has occurred. After all, the last grain could have landed prior to even leaving the top bulb. Therefore, the only correct solution is to put the hourglass into a sealed box where it is unviewable. After some set amount of time, remove the hourglass. If the cat is dead, then eat the sandwich.

Quote: konceptum

I would also vote for "other". Schrodinger shows that simply by observing the hourglass, you have no idea when the end of the time period has occurred. After all, the last grain could have landed prior to even leaving the top bulb. Therefore, the only correct solution is to put the hourglass into a sealed box where it is unviewable. After some set amount of time, remove the hourglass. If the cat is dead, then eat the sandwich.

Great post... But how do you know when to open the box?

You set two wires in the hourglass' constriction point witha small gap between them. You fill the top of the hourglass with conductive particles, say iron filings. As long as there is a current flowing, the circuit prevents the doomsday device from doing whatever it will do.

Easy, simple, foolproof and with an opening for the hero to McGyver it.

Quote: konceptum

I would also vote for "other". Schrodinger shows that simply by observing the hourglass, you have no idea when the end of the time period has occurred. After all, the last grain could have landed prior to even leaving the top bulb. Therefore, the only correct solution is to put the hourglass into a sealed box where it is unviewable. After some set amount of time, remove the hourglass. If the cat is dead, then eat the sandwich.

I was following allong until the last sentence. Then I had to ask: What if the sandwich was poisoned, and the cat is dead because she ate part of it?

Hits the pile

Quote: Ayecarumba

What event marks the end of the measured period when using an hourglass?

When the alarm timer starts beeping?

Quote: Ayecarumba

But how do you know when to open the box?

17 nanoseconds before the equilibrium point.

Quote: DJTeddyBear

What if the sandwich was poisoned, and the cat is dead because she ate part of it?

Rule 42.