Science questions not worth a thread I: I'm a moron!

[Cutlass]

It may work like adding salt to water to make an egg float. If the chlorinated water, like the salt water, is heavier/denser than regular water, then it goes downward and anything lighter goes upward.

 

[Timsup2nothin]

It may work like adding salt to water to make an egg float. If the chlorinated water, like the salt water, is heavier/denser than regular water, then it goes downward and anything lighter goes upward.

A second theory. And a good one.

 

[Timsup2nothin]

It may work like adding salt to water to make an egg float. If the chlorinated water, like the salt water, is heavier/denser than regular water, then it goes downward and anything lighter goes upward.

Thought about this for a while, and realized an update to the observed phenomenon is in order. Stuff doesn't just all bob up instantly, it takes time. If it was density change in the water it would be immediate result. I also did some math (apologies for the non metric units).

The hypochlorate solution is about ten pounds per gallon, and water is about eight pounds per gallon. Fighting a black pool I will put in two cases, which is eight gallons, in an ordinary size pool which is 15000 gallons. Density change is going to be about 1/1000 of a pound per gallon. I could convert that to a more traditional unit of density, but I think it is going to be really small no matter what.

 

[Samson]

Thought about this for a while, and realized an update to the observed phenomenon is in order. Stuff doesn't just all bob up instantly, it takes time. If it was density change in the water it would be immediate result. I also did some math (apologies for the non metric units).

The hypochlorate solution is about ten pounds per gallon, and water is about eight pounds per gallon. Fighting a black pool I will put in two cases, which is eight gallons, in an ordinary size pool which is 15000 gallons. Density change is going to be about 1/1000 of a pound per gallon. I could convert that to a more traditional unit of density, but I think it is going to be really small no matter what.

My initial thought was that you would need to add a lot of chlorine to water to change the density much. I know very little about this, but I believe that chlorine is an oxidising agent, so it would make sense if it was liberating some gas from some organic compound, or being used by some bacteria to produce some gas. This gas could cause the leaves to float. This is no less speculation than your initial hypothesis.

 

[Timsup2nothin]

My initial thought was that you would need to add a lot of chlorine to water to change the density much. I know very little about this, but I believe that chlorine is an oxidising agent, so it would make sense if it was liberating some gas from some organic compound, or being used by some bacteria to produce some gas. This gas could cause the leaves to float. This is no less speculation than your initial hypothesis.

I think that actually is my initial hypothesis. I'm pretty comfortable that the gas released from breaking down the organic compounds would be nitrogen...comfortable enough to claim it anyway. Chlorine is definitely an oxidizing agent; at least that is the controlled material category it is listed in and it will rust the heck out of any tool or truckbed it encounters.

 

[uppi]

Thought about this for a while, and realized an update to the observed phenomenon is in order. Stuff doesn't just all bob up instantly, it takes time. If it was density change in the water it would be immediate result. I also did some math (apologies for the non metric units).

The hypochlorate solution is about ten pounds per gallon, and water is about eight pounds per gallon. Fighting a black pool I will put in two cases, which is eight gallons, in an ordinary size pool which is 15000 gallons. Density change is going to be about 1/1000 of a pound per gallon. I could convert that to a more traditional unit of density, but I think it is going to be really small no matter what.

Both arguments do not totally defeat the density argument. If the stuff is buoyant in the water, a tiny change in density would result in a tiny force upwards which would let the stuff drift slowly to the surface. Add to that the time it takes for hypochlorate solution to dissolve and you would not expect the stuff to surface immediately.

It should be relatively easy to test: If he density change is relevant, it should also work with other substances like salt. So using brine instead of chlorine should also work. The fact that not-so-healthy chlorine is used might be an indication that less problematic substances do not work as well.

If nitrogen gas is formed, I would expect there to be bubbles before/when stuff surfaces. Do you see bubbles?

 

[Timsup2nothin]

Both arguments do not totally defeat the density argument. If the stuff is buoyant in the water, a tiny change in density would result in a tiny force upwards which would let the stuff drift slowly to the surface. Add to that the time it takes for hypochlorate solution to dissolve and you would not expect the stuff to surface immediately.

That's a good point.

It should be relatively easy to test: If he density change is relevant, it should also work with other substances like salt. So using brine instead of chlorine should also work. The fact that not-so-healthy chlorine is used might be an indication that less problematic substances do not work as well.

Not so easy to test. If someone provides me a black pool they actually are looking for me to fix it, not experiment on it. If I run into one where they are not in a hurry and I can get them to wait a bit in the interest of science...

But as a general rule the only reason they are paying me is because I make a good case for knowing what I'm doing, so suggesting experiments is a bit off my rails.

If nitrogen gas is formed, I would expect there to be bubbles before/when stuff surfaces. Do you see bubbles?

Some foaming is normal in the course of the cleanup, so yes.

 

[uppi]

Not so easy to test. If someone provides me a black pool they actually are looking for me to fix it, not experiment on it. If I run into one where they are not in a hurry and I can get them to wait a bit in the interest of science...

But as a general rule the only reason they are paying me is because I make a good case for knowing what I'm doing, so suggesting experiments is a bit off my rails.

Well, I was going to suggest to take samples (e.g. with buckets) and experiment on those. A whole pool is going to get more accurate results, though.

But I guess if the stuff was floating at levels where you could easily get it with a bucket, you would not need to get out the chlorine. Maybe you can fabricate your samples by taking a small amount of the stuff and dump it into a bit of water again?

Which brings me to another test of your theory: If you do not take it out, does the stuff sink again? If it does, this would point out that the floating is due to volatile components - once the gas is gone, it will let the stuff float anymore. If it does not, the change is more permanent: Either because the density of the water has changes or because you altered the chemical composition of the stuff.

Unfortunately, I fear that pool owners will not look too kindly on this experiment either

 

[Timsup2nothin]

Yeah, I'm thinkin' that "I'm leaving that there to see if it sinks" is probably not going to go real well. I was a poolman for a long time and I can't think of any circumstance where I would have said that.

Buckets though. I could scoop out a water sample, and I do blind net the bottom before I start so I could dump a netload into the bucket. And just take the experiment home. Brine in the bucket as a control, chlorine in the pool to do the job.

I don't think it is possible to make brine as heavy as the hypochlorate solution I use. Some calculations for how to get the desired change in density required. Should be doable though.

 

[Atticus]

Some foaming is normal in the course of the cleanup, so yes.

Is there a difference when the pool contains leaves and when it doesn't? If the nitrogen is produced in the leaves then there should be (or the foam isn't relevant).

 

[Timsup2nothin]

Is there a difference when the pool contains leaves and when it doesn't? If the nitrogen is produced in the leaves then there should be (or the foam isn't relevant).

Pretty much all black pools have some leaves in them, but even if they don't they are full of algae anyway...which from the chlorine's point of view is pretty much the same thing I think. Doesn't seem like there is much difference in the foam when there are a lot of leaves or a few.

 

[hobbsyoyo]

Thanks!, I appreciate the responses/answers.

No problem.

That story about the anomaly found last year on the bottom of the Baltic is just a YouTube scam?

Pretty sure it was.

Is there a theoretical upper limit on how large an implosion type atomic bomb can be?

You mean without boosters or going thermonuclear? Just a pure Pu implosion device?

 

[Cutlass]

You mean without boosters or going thermonuclear? Just a pure Pu implosion device?

Not the best worded query, I suppose. A fission device powers a fusion device. So far as I understand it, the typical fission device is a sphere of fissionable material which is surrounded by carefully designed and timed chemical explosives to compress the material until uncontrolled fission occurs. So your limiting factors, the purity of the fissionable materials, the degree of compression which can be forced by the explosives, the mass of the material which can be made into a sphere before spontaneous fission occurs. And then in the fusion device, that reaction is used to compress tritium or deuterium to the point of fusion. The Tsar Bomb was supposed to be about a 50 megaton yield, and that was the biggest bomb built. I was curious whether using this basic bomb architecture, anyone had ever worked out what approximately the theoretical limit of how powerful a bomb could be made?

 

[Timsup2nothin]

On your fission device you have the more efficient but more complex compression method...which is no doubt better for triggering a fusion device. But just for clarity, the much less efficient but much more reliable 'bullet' design should be mentioned.

Take a sphere of fissile material with a small hollow in the center and a shaft connecting the small hollow to the outside. Fill the hollow with tritium, not for fusion purposes but because it will produce free neutrons under neutron flux, increasing neutron production dramatically. A machined rod of fissile material matching the shaft is fired into the sphere with an explosive charge.

Since it only takes a single charge it is a lot easier to produce and will produce a fission reaction much more reliably, but since it is not being pressurized from all directions by explosives it blows apart much more quickly so less of the fuel fissions. Still plenty messy though.

 

[Eran of Arcadia]

A potentially unanswerable hypothetical . . .

If paleontologists who had never seen a dog before, discovered the fossilized skeletons of both a chihuahua and a great dane, would they be able to tell they belonged to the same species?

 

[Flying Pig]

Might be tricky, given that the only reason that we decide that they are is because they can breed together. Perhaps you could tell that with DNA?

 

[Michkov]

So your limiting factors, the purity of the fissionable materials, the degree of compression which can be forced by the explosives, the mass of the material which can be made into a sphere before spontaneous fission occurs.

You can add a reflector that bounces back neutrons that leave the pit to further increase the yield. Or reduce the amount of material needed to produce the same yield. Further the mass needed before spontaneous fission starts is dependent on the shape that mass takes. I.e. a sphere and a torus have different critical masses.

 

[uppi]

If you had enough DNA samples you could easily tell that they are the same subspecies. The nice thing about DNA is that you can trace interbreeding, so if you have enough samples of mixed dogs you can tell that they are able to breed.

But I believe the question was whether you could tell just from the morphology of the bones. I guess only someone having experience with paleontology can tell that, but I would doubt it. I am quite certain, there would be huge controversy whether to place the finds in the same species or not, with the consensus changing more than once.

 

[Timsup2nothin]

You can add a reflector that bounces back neutrons that leave the pit to further increase the yield. Or reduce the amount of material needed to produce the same yield. Further the mass needed before spontaneous fission starts is dependent on the shape that mass takes. I.e. a sphere and a torus have different critical masses.

Hence the term critical geometry.

 

[hobbsyoyo]

Not the best worded query, I suppose. A fission device powers a fusion device. So far as I understand it, the typical fission device is a sphere of fissionable material which is surrounded by carefully designed and timed chemical explosives to compress the material until uncontrolled fission occurs. So your limiting factors, the purity of the fissionable materials, the degree of compression which can be forced by the explosives, the mass of the material which can be made into a sphere before spontaneous fission occurs. And then in the fusion device, that reaction is used to compress tritium or deuterium to the point of fusion. The Tsar Bomb was supposed to be about a 50 megaton yield, and that was the biggest bomb built. I was curious whether using this basic bomb architecture, anyone had ever worked out what approximately the theoretical limit of how powerful a bomb could be made?

I don't know what the theoretical maximum is. I do know the Tsar Bomba, while tested at 50mt, was actually designed to scale all the way to 100mt.

As for minimum designs, I have read that there a few non-Pu/U fissile isotopes that give frighteningly small (theoretical) critical masses on the order of single-digit kilograms. Most are very hard to obtain in quantity and the rest weren't that necessary considering all of the Pu/U infrastructure that was put in place.