Best vid from Smarter Every Day I've seen yet!

Tags for this video have been changed from 'smarter every day, destin, destinews, polarity, mechanical failure front' to 'smarter every day, polarity, mechanical failure front, glass, prince ruperts drop' - edited by xxovercastxx

Hi @ant, the latest smarter every day features the ants we were hoping to see more of last time:

http://videosift.com/video/TONIGHT-WE-EAT-LIKE-KINGS-Smarter-Every-Day-81

It also has some links to ant info

Tags for this video have been changed from 'sixty symbols, vihart, cgpgrey, smarter every day, Minute Physics' to 'sixty symbols, vihart, cgpgrey, smarter every day, Minute Physics, vi hart' - edited by messenger

I'd already watched it but forgotten. I'm so suggestible. At least I'm learning.>> ^ReverendTed:

>> ^messenger:
My best guess: water would shoot out the top and bottom, and soon after, the sides of the bottle would be sucked in from the momentum of the water leaving and nothing replacing it.>> ^grahamslam:
So what would happen if he exploded it without the cap on it?

Exactly like we see in their "self portrait" burst. The top flies off and the sides of the bottle collapse inward.

>> ^messenger:

My best guess: water would shoot out the top and bottom, and soon after, the sides of the bottle would be sucked in from the momentum of the water leaving and nothing replacing it.>> ^grahamslam:
So what would happen if he exploded it without the cap on it?

Exactly like we see in their "self portrait" burst. The top flies off and the sides of the bottle collapse inward.

My best guess: water would shoot out the top and bottom, and soon after, the sides of the bottle would be sucked in from the momentum of the water leaving and nothing replacing it.>> ^grahamslam:

So what would happen if he exploded it without the cap on it?

What I'd really like to see is the same experiment, but with grid lines drawn on the bottles. I predict we'd see the "expanding jig" effect at the top.>> ^Boise_Lib:

My hypothesis is easily falsifiable. If the top half of a bottle had an expandable jig placed into it and the outer circumference of the top 1/3 of the bottle was stressed outward would the top portion be pulled down?
If you want to communicate with Destin be my guest--but I want credit when they hand out the Nobel.

The water is shooting out the bottom because of an explosion in between the bottom and the top. The force of the explosion is working in both directions, so water coming out the bottom is reacting to the same pressure was water in the top, and couldn't be drawing a vacuum from the other side of the explosion. Explosions pressurize in all directions.

To create a vacuum in the top, water would have to be creating suction by travelling down the bottle, away from the cap. Yet in frames 5-11 the collection of bubbles in the top half shrinks and stays in one place. That tells me that as the water shoots out the bottom, the water in the top half of the bottle isn't moving at all and remains pressurized by the explosion, so the evacuating water couldn't be creating a vacuum in the top.>> ^lucky760:

I would guess it's because of the vacuum created when that mass of water explodes out the bottom. In the instant it escapes, there needs to be something to fill the upper end of the bottle, so the top gets sucked down.
I'd wager that if they took off the cap the top of the bottle would no longer collapse (or if inadequate air was sucked in it would still collapse, but to a lesser degree).
But what do I know.

That's my hunch as well.
>> ^lucky760:

I would guess it's because of the vacuum created when that mass of water explodes out the bottom. In that instant it escapes, there needs to be something to fill the upper end of the bottle, so the top gets sucked down.
I'd wager that if they took off the cap the top of the bottle would no longer collapse (or it would still collapse, but less if inadequate air was sucked in).
But what do I know.

>> ^messenger:

I think you're onto something, but to me it looks a bit different. I downloaded it have been looking at the individual frames. The deformation wave from the bottom doesn't reach the top until after the bottle is too deformed by other forces. The top of the bottle, including the cap, started moving into the bottle in frame 2 of the explosion. In that same frame, you can see one point that's not moving in about half-way between the cap and the wide part all the way around. It looks like a bulge going out almost as fast as the top is coming in. That bulge forms the leading wave of the rest of the bottle coming up. If the cavitation was powerful enough to suck the top of the bottle in, surely it would also be strong enough to also suck the (much weaker) sides of the bottle in too, especially the point where the bulge starts, but in fact, the opposite happens.
You gonna tell Destin? If you don't, I will.>> ^Boise_Lib:
My thought is that the top area is slightly thicker and stronger. As the bottle circumference deforms outward it pulls the top down. It seems the top only comes down after the bottle is already ruptured by the pressure wave--that's why I think the pressure isn't affecting the top.



My hypothesis is easily falsifiable. If the top half of a bottle had an expandable jig placed into it and the outer circumference of the top 1/3 of the bottle was stressed outward would the top portion be pulled down?

If you want to communicate with Destin be my guest--but I want credit when they hand out the Nobel.

I think you're onto something, but to me it looks a bit different. I downloaded it have been looking at the individual frames. The deformation wave from the bottom doesn't reach the top until after the bottle is too deformed by other forces. The top of the bottle, including the cap, started moving into the bottle in frame 2 of the explosion. In that same frame, you can see one point that's not moving in about half-way between the cap and the wide part all the way around. It looks like a bulge going out almost as fast as the top is coming in. That bulge forms the leading wave of the rest of the bottle coming up. If the cavitation was powerful enough to suck the top of the bottle in, surely it would also be strong enough to also suck the (much weaker) sides of the bottle in too, especially the point where the bulge starts, but in fact, the opposite happens.

You gonna tell Destin? If you don't, I will.>> ^Boise_Lib:

My thought is that the top area is slightly thicker and stronger. As the bottle circumference deforms outward it pulls the top down. It seems the top only comes down after the bottle is already ruptured by the pressure wave--that's why I think the pressure isn't affecting the top.

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>> ^messenger:

Hadn't thought of that. So, the wave of deformation goes up the bottle, and pushes the top down?>> ^Boise_Lib:
I think the top is "sucked in" because of the deformation of the rest of the bottle.



My thought is that the top area is slightly thicker and stronger. As the bottle circumference deforms outward it pulls the top down. It seems the top only comes down after the bottle is already ruptured by the pressure wave--that's why I think the pressure isn't affecting the top.

Hadn't thought of that. So, the wave of deformation goes up the bottle, and pushes the top down?>> ^Boise_Lib:

I think the top is "sucked in" because of the deformation of the rest of the bottle.