My initial suspicion was the same as the host's - that the bottle was rocketing up and the cap was "overrun" by the rest of the bottle. That doesn't hold up to scrutiny since the cap "shrinks" back rather than staying still.

In their first explosion, the cap actually explodes very quickly after the burst. That seems relevant. I'm not sure how.

My second thought is along the "vacuum\low pressure" line of thinking. The entire bottle is pressurized in the instant of the explosion, and then ruptures at the bottom, so now the bottom of the bottle is lower pressure as water is rushing out, pulling the cap end down. Bernoulli principle, perhaps?
I imagine a bottle full of water, but it has no bottom. The water is rapidly and forcibly evacuated. The logical thing is for the cap to be crumpled downward.

Ooh, wait. Could this have something to do with the gas at the top of the bottle vs the liquid? I'm having flashbacks to the Mythbusters episode about the sinking car, and how the pressure of the water inside the car was lower than the outside as long as significant amount of air was left in the vehicle, so even though the water was up past the inside of the car door, it still couldn't be pushed open until the rest of the car had equalized. This seems relevant to me as well, though I'm not sure how, exactly.

>> ^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.

>> ^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.

Safe nuclear refers to many different new gen4 reactor units that rely on passive safety instead of engineered safety. The real difference comes with a slight bit of understanding of how nuclear tech works now, and why that isn't optimal.

Let us first consider this, even with current nuclear technology, the amount of people that have died as a direct and indirect result of nuclear is very low per unit energy produced. The only rival is big hydro, even wind and solar have a great deal of risk compared to nuclear as we do it and have done it for years. The main difference is when a nuclear plant fails, everyone hears about it...but when a oil pipeline explodes and kills dozens, or solar panel installers fall off a roof or get electrocuted and dies...it just isn't as interesting.

Pound per pound nuclear is already statistically very safe, but that isn't really what we are talking about, we are talking about what makes them more unsafe compared to new nuclear techs. Well, that has to do with how normal nukes work. So, firstly, normal reactor tech uses solid fuel rods. It isn't a "metal" either, it is uranium dioxide, has the same physical characteristics as ceramic pots you buy in a store. When the fuel fissions, the uranium is transmuted into other, lighter, elements some of which are gases. Over time, these non-fissile elements damage the fuel rod to the point where it can no longer sustain fission and need to be replaced. At this point, they have only burned about 4% of the uranium content, but they are all "used up". So while there are some highly radioactive fission products contained in the fuel rods, the vast majority is just normal uranium, and that isn't very radioactive (you could eat it and not really suffer any radiation effects, now chemical toxicity is a different matter). The vast majority of nuclear waste, as a result of this way of burning uranium, generates huge volumes of waste products that aren't really waste products, just normal uranium.

But this isn't what makes light water reactors unsafe compared to other designs. It is all about the water. Normal reactors use water to both cool the core, extract the heat, and moderate the neutrons to sustain the fission reaction. Water boils at 100c which is far to low a temperature to run a thermal reactor on, you need much higher temps to get power. As a result, nuclear reactors use highly pressurized water to keep it liquid. The pressure is an amazingly high 2200psi or so! This is where the real problem comes in. If pressure is lost catastrophically, the chance to release radioactivity into the environment increases. This is further complicated by the lack of water then cooling the core. Without water, the fission chain reaction that generates the main source of heat in the reactor shuts down, however, the radioactive fission products contained in the fuel rods are very unstable and generate lots of heat. So much heat over time, they end up causing the rods to melt if they aren't supplied with water. This is the "melt down" you always hear about. If you start then spraying water on them after they melt down, it caries away some of those highly radioactive fission products with the steam. This is what happened in Chernobyl, there was also a human element that overdid all their safety equipment, but that just goes to show you the worst case.

The same thing didn't happen in Fukushima. What happened in Fukushima is that coolant was lost to the core and they started to melt down. The tubes which contain the uranium are made from zirconium. At high temps, water and zirconium react to form hydrogen gas. Now modern reactor buildings are designed to trap gases, usually steam, in the event of a reactor breach. In the case of hydrogen, that gas builds up till a spark of some kind happens and causes an explosion. These are the explosions that occurred at Fukushima. Both of the major failures and dangers of current reactors deal with the high pressure water; but water isn't needed to make a reactor run, just this type of reactor.

The fact that reactors have radioactive materials in them isn't really unsafe itself. What is unsafe is reactor designs that create a pressure to push that radioactivity into other areas. A electroplating plant, for example, uses concentrated acids along with high voltage electricity in their fabrication processes. It "sounds" dangerous, and it is in a certain sense, but it is a manageable danger that will most likely only have very localized effects in the event of a catastrophic event. This is due mainly to the fact that there are no forces driving those toxic chemical elements into the surrounding areas...they are just acid baths. The same goes for nuclear materials, they aren't more or less dangerus than gasoline (gas go boom!), if handled properly.

I think one of the best reactor designs in terms of both safety and efficiency are the molten salt reactors. They don't use water as a coolant, and as a result operate at normal preasures. The fuel and coolant is a liquid lithium, fluoride, and beryllium salt instead of water, and the initial fuel is thorium instead of uranium. Since it is a liquid instead of a solid, you can do all sorts of neat things with it, most notably, in case of an emergency, you can just dump all the fuel into a storage tank that is passively cooled then pump it back to the reactor once the issue is resolved. It is a safety feature that doesn't require much engineering, you are just using the ever constant force of gravity. This is what is known as passive safety, it isn't something you have to do, it is something that happens automatically. So in many cases, what they designed is a freeze plug that is being cooled. If that fails for any reason, and you desire a shutdown, the freeze plug melts and the entire contents of the reactor are drained into the tanks and fission stops (fission needs a certain geometry to happen).

So while the reactor will still be as dangerous as any other industrial machine would be...like a blast furnace, it wouldn't pose any threat to the surrounding area. This is boosted by the fact that even if you lost containment AND you had a ruptured emergency storage tank, these liquid salts solidify at temps below 400c, so while they are liquid in the reactor, they quickly solidify outside of it. And another great benefit is they are remarkably stable. Air and water don't really leach anything from them, fluoride and lithium are just so happy binding with things, they don't let go!

The fuel burn up is also really great. You burn up 90% of what you put in, and if you try hard, you can burn up to 99%. So, comparing them to "clean coal" doesn't really give new reactor tech its fair shake. The tech we use was actually sort of denounced by the person who made them, Alvin Weinberg, and he advocated the molten salt reactor instead. I could babble on about this for ages, but I think Kirk Sorensen explains that better than I could...hell most likely the bulk of what I said is said better by him



http://www.youtube.com/watch?v=N2vzotsvvkw

But the real question is why. Why use nuclear and not solar, for instance?

http://en.wikipedia.org/wiki/Energy_density

This is the answer. The power of the atom is a MILLION times more dense that fossil fuels...a million! It is a number that is beyond what we can normal grasp as people. Right now, current reactors harness less that 1% of that power because of their reactor design and fuel choice.

And unfortunately, renewables just cost to darn much for how much energy they contribute. In that, they also use WAY more resources to make per unit energy produced. So wind, for example, uses 10x more steal per unit energy contributed than other technologies. It is because renewables is more like energy farming.

http://videosift.com/video/TEDxWarwick-Physics-Constrain-Sustainable-Energy-Options


This is a really great video on that maths behind what makes renewables less than attractive for many countries. But to rap it up, finally, the real benefit is that cheap, clean power is what helps makes nations great. There is an inexorable link with access to energy and financial well being. Poor nations burn coal to try and bridge that gap, but that has a huge health toll. Renewables are way to costly for them per unit energy, they really need other answers. New nuclear could be just that, because it can be made nearly completely safe, very cheap to operate, and easier to manufacture (this means very cheap compared to today's reactors as they are basically huge pressure vessels). If you watch a couple of videos from Kirk and have more questions or problems, let me know, as you can see, I love talking about this stuff Sorry if I gabbed your ear off, but this is the stuff I am going back to school for because I do believe it will change the world. It is the closest thing to free energy we are going to get in the next 20 years.

In reply to this comment by ReverendTed:
Just stumbled onto your profile page and noticed an exchange you had with dag a few months back.
What constitutes "safe nuclear"? Is that a specific type or category of nuclear power?
Without context (which I'm sure I could obtain elsewise with a simple Google search, but I'd rather just ask), it sounds like "clean coal".

PRO-TIP: Rotate your plasma cutter to a vertical orientation and aim for the arm joints to take out this nasty necromorph. If you accidentally hit the stomach causing it to rupture, prepare to run as a swarm of smaller necromorphs burst forth from the fallen carcass and attack you like a squirmy blanket of death.

I like how we are being all buddy buddy now. It makes my face rupture with smiles galore. Often I think maybe I should save my down vote for after a video sifts, but that really requires a lot of after thought on my part. I am not great with work after the fact. I am more of an impulse voter.


In reply to this comment by JiggaJonson:
I don't sift that often any more, meh, I thought I found a diamond in the rough here.

69,327 likes, 2,215 dislikes on Youtube at the moment.

And just as it was climbing up, and had a glimmer of hope, you had to shut me down for...? Oh right. Because you "Don't come here to waste time" ಠ_ಠ

I guess not all of us can post classic non-time-wasters like Alice in Wonderland Porn: http://videosift.com/video/Alice-in-wonderland-porn-scene

Some different views and analysis here.
http://videosift.com/video/Sgt-Kayvan-Sabeghi-Ruptured-Spleen-in-Oakland-Countdown

>> ^GenjiKilpatrick:

@WaterDweller & @radx
You do realize the plane had a small jet engine in it, right?
If the battery did fail [most likely rupturing/exploding], it could have damaged the engine triggering the explosion.

Yes, that's a very good hypothetical explanation. I would have thought the same, hadn't it been for the video explicitly showing the planting of the bomb, with him even saying so ("ich habe ein kleines bömbchen gebaut" -- "I have built a little bomb").

@WaterDweller & @radx

You do realize the plane had a small jet engine in it, right?

If the battery did fail [most likely rupturing/exploding], it could have damaged the engine triggering the explosion.

I was also disappointed by the lack of paintballs actually rupturing against human targets, but upvote for the cool idea, slow-mo capture of the spread and ruptures against walls etc., and potato gun air-guitar ending...

You got hobbling right? We shall hobbit people.

But there's the risk of one or both parties crying foul. There's also the risk of moderator mis-use Reddit style.

See the creation of /r/trees, and the close destruction of /r/starcraft.

Not saying you don't have to do something, but you'll never get away from the drama. You just replace one sort of drama with another sort of drama. Which one is worse?

Granted moderator misuse would probably happen less often then comment abuse, it would have much more impact on the community as a whole, as tyranny always does. So in a way transferring the responsibility to the user base is going to gut you're workload, in a good way and insure that the comments get a good seeing too, but the problems that arise have a chance to blow up into a community rupturing event.

What I mean to say, is that what starts out as a way to control asshat comments can turn into a way for users with a vendetta to destroy those they don't agree with, or those they don't "like".

The worst kind of tyranny is the kind where the rules creep. Rules are laid down in good interest and then are enforced differently than they were written. Kinda like Feature Creep but worse.

Eh, but I'm pretty indifferent to what the community decides mostly because I treat the internet as I would my cat. I feed it, I pet it, and I love it, but at the end of the day I just let it do whatever the fuck it wants to do.


PS: I haven't got anytime to edit my comment for spelling and grammar. If I derped it up, then herp derp.

>> ^ForgedReality:

People, take the fucking masks off. SARS is the LAST thing you should be worrying about.
How about your house falling into a sinkhole; or getting sick when a sewage line breaks and ruptures up through the street; or a broken water main flooding the city; or a building falling on you.. Oh and let's not forget radiation everywhere, and how you can't eat any of your own food anymore....
Look, no offense and all, but sucks to be you, bro.
edit - Isn't it spelled "liquefy?" >_>


Many people wear the masks whenever they're going to be out in public. It's not SARS so much as any number of things that might be floating around in a city where so many people live so close to one another. And disease outbreaks follow natural disasters.

People, take the fucking masks off. SARS is the LAST thing you should be worrying about.

How about your house falling into a sinkhole; or getting sick when a sewage line breaks and ruptures up through the street; or a broken water main flooding the city; or a building falling on you.. Oh and let's not forget radiation everywhere, and how you can't eat any of your own food anymore....

Look, no offense and all, but sucks to be you, bro.

edit - Isn't it spelled "liquefy?" >_>

That is absolutely all kinds of funny.

If they can pull that off in the game I will not buy it. Too afraid of a massive rupture from laughing too hard for too long.