Explosion: CR4 Challenge (03/10/09)

Hi, FKIA!

You mentioned, "matter is what atoms and molecules are made of. Matter is commonly said to exist in four states (or phases): solid, liquid, gas and plasma; other phases, such as Bose–Einstein condensates, also exist."

In a deeper sense, matter is energy slowed enough to form particulate. In that regard, it might be considered that the basic state of matter is energy. It can be present in solid, liquid, gas, and plasma, and in its slowest existence, the crazy condensate where it loses the need for any kind of form.

This continuum of existence beginning (so far as we know) with energy and extending (in our time) to Bose-Einstein condensate begs the questions as to what differentiates matter when it slows below the speed of light, and whether mass exists for all states; and brings into play the extremely wild idea of perception as a key event in the creational force of both energy expression (it can be "seen", it "shines", it's "cold", it's "hot", etc. etc.) and matter identification (it has mass, it has a specific gravity, it weighs, it possesses tactility, strength, acidity, one a day keeps the doctor away, and so on.)

In the pre-matter stage, energy has no identifiable mass and we have thus far not been able to weigh it. Post-matter, it has mass and may be affected by gravity.

The point I am attempting to support here is that regardless of the style of energy and the state of matter, at some point all are combined in the article "bomb", and placed in the impervious box. The box lies outside of the universe of known possibility since it remains unable to experience any change in its nature; and so acts as an unalterable theoretical constant in the question.

After the bomb is detonated within the box, it becomes dozens of forms of matter and energy, none of which may escape from the box or combine with it. what it becomes is what it was all along, except in states of matter and energy characterized by pre- and post-explosion. Much of the matter's energy component will have been accelerated/converted into energy by the contagion of elements or actions we have developed to create that conversion.

e.g. By striking a match we can convert the chemical structure of the match to heat and light energy forms, and by applying those forms to a piece of paper, convert it also into carbon and vapour and byproducts such as heat and light . By the application of chemical reaction and force, we have been able to break the covalent bonds of the nucleus of certain atoms and release the energy that was used to hold them together, causing their various components to ricochet into other atoms and break them as well in a chain reaction. The energy is transformed, not created. We use the term "released".

All of this takes place inside the box, and nothing escapes (or combines with!) the box.

The question seems to center around whether when parts of the bomb are converted into energy of various stripes, does it lose mass? And if it does, is the overall weight of the bomb (and hence the bomb plus box) affected? If the paper we lit up a couple of paragraphs ago converts to ash and vapour, and we weigh the paper pre-ignition, and the ash and vapour post-ignition is there a weight difference? If so, then the energy released must have weight; and if not, then the energy released has no weight and doesn't count for any change in the weight of the substance formerly known as paper and now as ash plus vapour.

After being converted to heat plus vapour, how much weight is lost by the rods in an atomic furnace? When a light bulb burns out, does it weigh less than when it was new? Even if parts of the tungsten filament were vaporized when it parted, the glass bulb still contains that vapour, and weight doesn't change.

Apparently, in the re-conversion of matter back into energy where the basic substance of the matter still remains, there is no measurable difference in the weight. We've removed some of the energy component, but not the matter component.

After the explosion, the basic substance of the bomb still remains locked within; so the box should weigh the same both pre and post detonation.

Mark

Just for interest sake....

Here is a brief, simple explanation of some photon mass theory.

http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html

.. which shows that great minds think alike.

I post this as rhetorical, but feel free to comment if you wish.

Interesting link. But I think it is flawed on the outset.

"Does the photon have mass? After all, it has energy and energy is equivalent to mass."

I think the "energy is equivalent to mass" is the flawed part. This may be a theory, and it may be a fact. But it is not known to be fact. If heat is energy and therefore heat is mass, then, if I have a glass of water at any temperature above absolute zero, what mass or matter is in the glass besides good old H₂O that can be identified as heat? And, how can you prove it is there without resorting to circumstantial evidence, as circumstantial evidence is not fact. I think we get into trouble when we try to construct fact by basing it on a foundation of theory. And, I think that any answer to the original question can only be based on theory. My theory, your theory, or anyone else's theory. So, whatever the answer that is ultimately posted, you may have just as many dissenters then as now.

I think we can take "mass-energy equivalence" as fact: the bombs we make work as predicted. But saying "energy is equivalent to mass" casually, has a different meaning than "mass-energy equivalence." There is no equation that says E=M, and few of us claim that heat has mass, but Bob may be right.

So, whatever the answer that is ultimately posted, you may have just as many dissenters then as now.

Or more. There have been some of these questions on which maybe 60 or 70% of us agree that the official answer is just plain wrong.

so then there is no rest mass known for a photon, but it is suspected there is one? The article link did not seem to come to conclusion, and summate, though I have to admit I am deficient when it comes to a full grasp of equations.

I am inclined simply to accept that the Box and everything that Happens in The Box is fully isolated. Nothing can be lost or gained in the box.

Then I ask myself, what happens if the Box, a Metaphor for the Universe falls into a Wormhole, or a Black Hole?

Is then a shadow universe of Dark Matter explained by boxes of universes in conflict with universes that are not in boxes?

It would help me be a better thinker if one of you would give me an equation, right or wrong, that represented an inbox and out of box interaction of universes, wherein one universe did get lighter, and the other did not.

Love Russell P.S. I do not always sign off with Love, but really I love some of this sort of go around more than TV, or carpentry.

The article says "is said to be massless". But I found the explanation that followed was not as clear as it might be.

We can say one of two things about a "stationary" photon": we can say that the rest mass is identically zero, or we can say that a photon only exists if it is travelling at the speed of light. The statements are equivalent, because an object without charge, spin or mass might has no way of interacting with anything else.

We can deduce the zero rest mass from the fact that the photon travels at the speed of light - and the effective mass of an object travelling at the speed of light is an infinite multiple of its rest mass.

I hope that makes some sort of sense...

if it is zero than it will have no effect on the weight of the box, right?

Hi, Transcendian!

"so then there is no rest mass known for a photon, but it is suspected there is one?"

My thinking on posts regarding this question is that we were making up the answers to it based upon known and widely accepted theories and equations that allow for us to solve for it, as it were, backwards.

I actually don't know that anybody has a supported answer yet .

We know that certain photons have a definite lifespan, and thus a readily definable length; so it would seem in human experience that its possessing a mass is not out of the question.

But since it is a light particle and potentially travels in --and reacts with-- objects in a variety of ways, how could you find out?

And, after a theoretical physicist specializing in them determines an answer, will you understand it?

Mark

You know, the Challenge creator tried to keep it simple, yet the nerds in us (yes, you) keep ripping it into pointless minutiae. See if this helps:

The box is not a box; it is a three dimensional border. It has no walls, it is just a limit. It doesn't reflect or transmit; you can't see in, nothing gets out. It weighs nothing. It's impossible, but there it is.

The total weight of the volume within consists of the weight of the bomb and the surrounding air, vacuum or whatever.

Now: more, less or the same?

The question clearly says "You blow up the bomb.", implying an action. Floram's timer cannot be considered since that reduces "you" to a passive role. Therefore, "You" must add energy in order to signal or cause the bomb to explode. That energy adds weight. At first thought, we have to say the weight is now greater. However, the post clearly says "You blow up the bomb.", not "You signal the bomb to blow up.". So, you have to be able to confirm it blew up. That requires a signal of some sort back to you, and that signal carries weight away. In the only possible solution, given limited facts, we conclude the two signals have equal weight and cancel. Thus, the weight remains constant since that is the only possible definite answer.

obviously it will weigh less ,as some mass has been converted to energy.

Just looked up definitions. Which of over 10 definitions for "box" are we to use? "Indestructible" means simply not able to be destructed, nothing about whether particles, heat, or other stuff can be transmitted through or around the material the box is made of. Would a "box" made of some type of "indestructible" fine mesh fall into our definition of the container for this solidly constructed atomic bomb. I do agree that an exploded bomb converts some of it's "mass" into energy, however, if contained in a "box" from which it cannot escape, I believe the change in mass of the "box" system (box and bomb) will not be changed. I still say the framer of the theoretical question needs better definitions of it's parameters in order for any real answers to come forth. What did he/she/it really want to know? The mass of the system of box and bomb, the box alone, the weight of the box system, or the weight of the box alone, the effects of the change of relationships of matter to energy as they relate to mass, weight (relation of mass as measured as a relation to another massive object) or some other unknown thing the questioner wants to know but is not letting us in on. This did generate a lot of thought process, write or wrong (pun intended as to the spelling of "write" versus "right"). No definitive answer can come of the question as put forth. Or maybe, my last sentence is the definitive answer as the question is put forth!

Try the following:

If said box is "meshlike" and stuff can fall through then the mass of the box alone will not change as we should have massed it before placing the bomb in it in a vacuum and should do likewise after the explosion under the same exacting conditions on the same planetary body it was first massed on to determine if the mass of the box alone has changed, per the scientific method. This assumes the questioner at their word alone wants the answer to "does the box weight (mass) more...."

Then there is:

If the box system is the measured quantity as follows:

If said box is a solid box in which nothing can change it, leave it, enter it and it is totally enclosing on all sides in all 4 dimensions (time is number 4) and we assume the bomb has indeed exploded, as we cannot tell externally because no matter, energy or other particles or substances we can use to measure such an event is assumed to be able to leave it or enter it, then there will be no change in mass of the box/bomb system due to the fact that the matter converted to energy in the detonation of the bomb will have the mass of the matter converted contained within the box bouncing around for all eternity until it is slowed down by it's collisions with the matter also bouncing around inside the box converting to more energetic motion of the matter said to be bouncing around within the box.

WOW, what a digit full (digit being the term for fingers used to type this).

I give up. Pointless nitpicking over needless semantics. Nerds win.

Does it matter if the bomb is atomic or not? Surely energy is "released" even if the bomb released no more energy than a simple kitchen match igniting. For this type of bomb, indestructible would mean the box needed be made of nonobtainium but could be made of real world materials. While I am sure we don't have any instruments that could measure a change in mass or weight associated with the release of a small amount of energy, surely E=mc² applies just as much to chemically related energy releases as it does to nuclear energy related releases. The box and contents must weigh less even if only non-detectbily less.

Does it matter if the box can expand thermally due to the heat released by the bomb explosion? Even if there was no mass decrease (but there really is), an expanding box not in a vacuum would weigh less because it is taking up more volume and is more buoyant. The box and contents must weigh less.

Does it matter if we agree on what "indestructible", "blow up", or "weight" mean? I think we all have our own definition of these words and these definitions change with context and with how our opinions change. Sometimes the apparently most poorly posed challenge questions get the most insightful responses about how we approach problems. Usually the hardest and most rewarding part of problem solving is figuring out what the problem really is. Must be part of why this blog is so interesting.

Sometimes the apparently most poorly posed challenge questions get the most insightful responses about how we approach problems.

And as Michael Feldman says: "All questions used on "Whad'ya Know?" have been painstakingly researched, although the answers have not. Ambiguous, misleading, or poorly worded questions are par for the course. Listeners who are sticklers for the truth should get their own shows."

With all these challenge questions, much of the ambiguity can be dealt with by a statement of assumptions as part of a proposed answer. Of course, then the arguments over reasonableness of assumptions often occurs. The "Burglar / BB's " is a good example of this. In that thread, I argued at some length that the only reasonable assumption to make regarding the shooter "pointing" the gun and then shooting is that he "aimed" the gun -- otherwise, why would be pull the trigger, knowing that he could not possibly hit the burglar, because he has failed to aim (a process which involves pointing the barrel increasingly higher with distance to compensate for trajectory.) (This is the "monkey in a tree problem" seen in elementary physics texts, and in about half those texts, it is incorrectly phrased.)

These challenges can be as much about communicating as they are about the underlying science or engineering. Which is not a bad thing. All this helps to keep us thinking. And helps us change our thinking, which I have done in this thread, with the patience assistance of BobD.

I always remember at school, that my Teachers always were annoyed by my inquiries.

"do mean this, or that? it can also interpreted like this" Making precise informative, to the point "challenges" is also an art

Hi Jim,

You are contending that any matter converted to energy will then not contribute to the weight of the box even if that energy is still contained within the box. This is a common belief amongst many of the responses. Please refer to my response #70 and some subsequent correspondence that may clarify this. With a blog of this size it is hard to read all the responses.

No: I think that Jim, like Ken and I has come round to your way of thinking.

The obvious inference is that in any exothermic reaction (not just a nuke) some mass is converted to energy which may or may not get out of the box depending on the various possible interpretations of indestructible.

My 13 year old daughter has come up with a theory: that the box will weigh more when it has exploded because; there will only be a tiny amount of the bomb in contact with the box, so there will be more pressure on a small surface area. But when the bomb has exploded there will be more of the bomb in contact with the box; so the weight of the bomb will be spread over a larger surface aea, so the amount of pressure on the box will be less, because it will be spread over a wider surface area.

Considering that in several of the recent challenge problems there have been deficiencies relating to spelling, grammar, semantics, etc. it would appear that CR4 is slightly challenged with regard to getting and retaining competent and committed people to run this department. I suppose the Global Speconomic meltdown affects just about everyone.

It is evident that much of the interesting discussion gets generated by nit-picking on just these issues! However, although the present challenge is on a topic I know nothing about (beyond having enjoyed reading George Gamow's popular books over forty years ago), there seem to be some fundamental issues at stake here. I think it would be in order to try and rephrase the problem in the spirit in which it was intended (as far as my interpretation goes).

"If a violent nuclear reaction such as a bomb explosion occurs within a hypothetical sealed chamber which is indestructible and whose walls are completely impervious to passage of matter or energy in any form, will there be a change in the mass of the chamber including its contents?"

Some of the answers seem to be on these lines, but I am in no way qualified to comment. =TeeSquare=

Talking to a non nerd coworker about this this morning set me off on this train of thought:

Start with the answer being looked for: does the BOX weight more or less than before the explosion.

1) "weight" the box initially and call this number B

2) Place bomb in box and "weight" . Call this number B+C, C being the weight of the bomb

3) at this point notice the box and bomb are still on the scale and the scale reads a larger "weight" than just the box by merely placing additional mass of the bomb on the scale inside the box.

4) blow up the bomb

5) notice whether contained in totally or not in the "box" there will be either all the resultant mass of whatever is left of the bomb or some residual mass that will drift down onto/into the "box", no matter if it is only one atom or a big pile of 'em. the result is there is still the equation B+ something even if something is C - (C-1 atom)

Remember the question is: does the BOX weight more after the explosion. It weighed more simply by adding the bomb as well as after only the residuals of the bomb are left on or in the box.

Answer is: box weighs more because stuff has been added to the box though the amount of stuff may be varied depending on whether it is a full bomb or the leftovers and the box is still on the scale "weighing" the whole system of box plus whatever modifications we have made to it and it's system.

Now if you want to empty the box and clean it of any debris and remembering it to be indestructible I assume nothing will remain we again "weight' the box we will find it "weighs" the same as B as it is indestrictible and we cannot change the structure of the box proper.

Now, the box "weighs" neither more or less than before the explosion! This was not even given as a possible answer to this goofy question.

You are all missing the obvious. The box, if it is somewhere, anywhere, is surrounded by something. Even if that something is the sutff between the stuff. (dark mater)

The collapsing pulse of the nuke would create an in-rush of energy to the box.

You said it was indestructable not impenatratable.

For a nanosecond the box would definately weigh more.

Also, the reflection of the in-rush would probably suspend/distort gravity as it distorted/compressed space time.

Time to get back to the reactor in the basement :)

Ok, I fold.

The box has to be made of something if it can be defined as an indestructable box. There is more space between the atoms in the box than the sum of the atoms parts.(the stuff between the stuff) It is swiss cheese to the mater converted to energy in the explosion.

The energy leaks out. The the weight of the box is less.

It has to be within a gravitational objects influence to have weight so the "on what planet" thing is lame.

One last kick at the cat. An atomic explosion creates light in all directions. Light exerts force on objects that it impacts. If the box contains the light and it bounces around while you weigh the box, the weight will be less because 1/6 of the light,(it's a box), is also pushing on the top of the box, away from the gravitational force. The original weight of the box and bomb were all under the influence of gravity. I may be wrong but I think the same may apply to more exotic forms of the radiation created in the explosion.

I agree the what planet comment I made was lame. It was a feeble attempt at demonstrating there really are not enough limits made on the seemingly simple problem to make a really intelligent solution. The problem needs to be better defined as one other respondent attempted to do.

Then the question would not have generated such heated results, would it?

To paraphrase Mary Poppins, "A little ambiguity makes the solution go round and round.."

At least that's my take on all this.

Frankly, I have enjoyed the various answers, and while I do not agree with some, all make valid points in their own way.

Ken Leigh

Does Schroedinger have anything to say about it?

Spoken like a true cat.

I think since matter is being converted to massless particles that it will be lighter.

However, after the blast the temperature in the box will be much higher, not to mention that there will be radiation particles flying around at high speed. According to relativity, as I understand it, these particles will have a larger effective mass. My questions are:

1. Does relativistic mass lead to a larger gravitational interaction? Or is "relativistic effective mass" only relevant with regards to inertia?

2. If this relativistic effective mass does lead to an increased gravitational interaction, is it negligable or could it actually offset the mass lost when some mass was released as energy in the form of light which of course is massless?

Anyone who wants to help me here, it will be appreciated.

Roger

My Wife and I bought an Ecosphere that was a glass bubble with a living krill in it with water and some stuff. Pretty interesting how long the Krill lived in the glass bubble.

Light came in the glass.

Unless light came into the glass bubble where the krill lived, the krill would have died very much sooner. The weight of the glass, and the water, and the stuff inside the glass bubble did not change when the krill finally died. Or did it?

Does it make a difference if the indestructible box is clear like glass, and either lets light in, or lets light out?

Sorry I didn't get on with this sooner.

When pondering the weight of energy, and the difficulty in measuring it with a bathroom scale, I considered the electrical energy I use in my house each month: something like 500kWh. For calculations like this, Google is my friend. I typed in "500kWh/speed of light squared" and it spit back, in a fraction of a second:

(500 kilowatt hours) / (the speed of light squared) = 20.027701 micrograms

The 'official answer' is preposterous.

So not only is the box 'indestructible' it's also thermally inert. It can absorb all the energy from the detonation of an atomic bomb with no gamma, x-ray, radio or thermal energy escaping -- without even getting warm on the surface. Without even a whisper of an EMP pulse.

This box isn't just made out of 'Unobtainium', the box is grounded to a zero point energy well.

Well that's exactly the right question of course. The only way to be sure it exploded would be to monitor the box with detectors measuring gamma rays, x-rays, etc. The only way the box (i.e., the box and its contents) could remain the same weight would be if no energy whatever escaped. But if no energy escaped, your detectors would pick up nothing, indicating no explosion occurred.

Catch-22.

I suspect one could search the web all day long and never encounter a definition of "indestructible" that means incapable of being heated or radiating heat. When all else fails it makes sense to pick up Webster's, where we find that indestructible means incapable of being destroyed. To extend that to mean incapable of absorbing or emitting heat, incapable of transmitting any form of radiation, incapable of existing in anything remotely close to the real world, seems silly and completely illogical. A nuclear bomb is a real device. Why enclose it in a fictional enclosure?

An indestructible box for a dynamite explosion is easy to visualize. Jumbo, the container for the possible Trinity dud was not destroyed by the blast, so we can see that the idea of in indestructible box is possible, for a nuclear bomb too -- it is only a matter of scale.

Good question, unsatisfying official answer.

Hi, Blink!

The imaginary box, though, was used to describe a finite limit. It was a metaphor used to arrive at the conclusion. The end was deliberately arrived-at and the means created out of whole cloth as a "what if...?" fairytale.

An indestructible box is one of those unfathomable items that falls into the same category as a boundless universe or infinite time. Difficult to wrap one's totally destructible, finite, and lifespan-limited mind around it. Where could it have come from? How could it have been constructed? How could one get a bomb inside it? How could the bomb be detonated? What happens then? Mind games we get to play with ---or ignore--- in this Challenge Question.

Of course, there are all kinds of alternative discussions, all of them good. That's what made this question a nice little mind-stretcher, I believe. We had to suspend our disbelief...like watching a good movie...in order to get into the mechanisms of the question and compare them in a hundred different ways.

Mark

Hi Mark,

It was a metaphor used to arrive at the conclusion.

If the box is a metaphor, then we can only discuss the mass-energy equivalence of the energy expended in thinking about the box. For the question to make sense in an engineering or science forum, I think we have to assume that the box is intended to be real, just as the bomb is intended to be real. If the author intended the box to have extraordinary properties, then he should have stated those properties. Otherwise, the discussion quickly becomes one of subjective reality and cognition, rather than physics, which many of us think of as hard science: How objects that we agree to call "real" and "physical" behave when acted upon or when acting.

Suppose the author asks, "How much force is required to push a 10 kg box along a flat floor (at a constant speed), given a coefficient of friction between the floor and box of .2?" It would be unreasonable to assume that the box is bolted to the floor (and that the "constant speed" is zero) and that therefore a very large amount of force would be required to shear the bolts. It would also be unreasonable to assume that the box is on a spacecraft or another planet. It would also be unreasonable to assume that the pusher has to operate with zero friction (because the pusher's friction was not explicitly stated). Such logical leaps fall into the "jumping to conclusions" category. It is similarly unreasonable to assume that any indestructible box is impervious to energy transfer -- that goes well beyond even our silly assumption that the box is bolted to the floor, because while we know that boxes can be bolted to the floor, we know there are no impervious materials.

We have seen that materials as simple as plain dirt can contain the downward blast of a nuclear bomb: the crater from the Trinity test is fairly shallow -- clearly the people who assumed that the entire earth would be destroyed were wrong. Nuclear blasts are big and hot, but not magical. We know that an indestructible box can be built and used in a perfectly practical sense to contain a fire cracker explosion, and we know that indestructible boxes are routinely used to detonate small bombs found at airports, etc. These indestructible boxes do not have the magical properties that you are assigning to the box referenced in the question: the bomb squad boxes get warm, and then cool off -- and no sane person would describe the box as having been "destroyed" by that heating and cooling.

So, 1. given that we have many common definitions of indestructible that do not mean "impervious to all energy" and none that do mean "impervious to all energy" and 2. given that we have practical examples of indestructible boxes which are used in exactly the same way as the author proposed, (the only difference being scale), then we have to apply Occam's Razor. We should 1. refrain making up silly conditions (such as the box cannot shake or vibrate) and 2. refrain even more strongly from making up magical conditions (such that the box cannot be heated and radiate heat or that the box possesses no mass). To suppose that the box cannot be heated and cannot radiate heat takes the discussion from ordinary physics to the fringes of philosophy in one very large leap.

If the box is purely metaphorical, then the bomb must also be metaphorical, in which case, the energy invested by all the people thinking about this problem (and the separate issue of whether that energy is part of the metaphorical box and bomb or not) is simply impossible to measure in any remotely realistic sense.

To suggest that imperviousness is a condition for indestructibility is to say that a glass bottle has been destroyed when light is passed through it. That is a highly subjective reality that I cannot buy into.

Will all the people here who believe in telekinesis please raise my hand?

The exchanges between you and Mark go pretty deep, but I feel much of it is off-track. Without getting into details, I'd like to just question your statement "... If the box is purely metaphorical, then the bomb must also be metaphorical ...."

Mark has addressed the issue quite plainly in #150 (compared to my amateur effort in #107). The box is quite incidental to the question, which is essentially about mass changes during a nuclear reaction. I think it is not even necessary to imagine that the nuclear reaction is restricted to a confined space. The box 'metaphor' only helps us to 'imagine' that the mass (or weight) before and after the event can by measured. Though to me it is inconceivable that such measurement is practically possible, I am still curious to know the following:

With the accepted state of knowledge about nuclear explosions and the kinds of particles and waves which are generated, together with the mass-energy equation and quantum mechanics and whatever other theories are involved, will there be a net increase or decrease in the total mass of the participating ingredients?

Maybe one could suppose that the reaction takes place somewhere in interstellar space where there is no other matter (mass) and any background radiation does not influence the reaction.

If a confined chamber is postulated to create a fixed volume, it can be supposed that the inside surface is perfectly elastic so that particles will bounce back with no loss of energy, and also perfectly reflective for all radiation. There will then be questions about the effect of pressure and temperature build-up on the progress of the reaction, but those are points which can be meaningfully discussed, rather than the impossibility of creating indestructible chambers.

I must admit that my (mechanical engineering) imagination does not extend much beyond nuts and bolts and newtonian mechanics, but I'm still finding this discussion interesting! =TeeSquare=

So then relativistic effects don't matter here? I mean, confining a nuclear blast to a box will get awfully hot, right? At what temperature do relativistic mass become a factor?

Hi, Roger Pink!

I don't think it's temperature, so much as quantity, where relativistic effects become a factor. Think of a small amount of sunlight*. Not too hot. Now think of lots and lots of sunlight. Much warmer.

Mark

*or more current into a resistance coil to make it hotter; or more surface area as its _Cf (frictional coefficient) becomes applied when rubbing on another surface to raise its temp; or cooling speed with a larger heat sink volume than source; maybe even entropy where a renewed source of energy has not been applied.

Hi Roger Pink,

We are trying to keep a nuclear blast and bomb proof box relatively simple. (As if)

If you can contain the energy of a nuclear blast would you not get a much better yield from your fissile material?

There is so much fun to be had moving from impossible sitation to probable conclusions.

BAB

So it was all just Hot air?

There was never a bomb it was all a dream a true dallas ending

I submit adding three words to the question and you then get closer to the "official" answer. Try: "totally enclosing, impervious, " to be inserted directly in front of the word "indestructible '.

I go back to my other responses and the look into the definitions of the words of the challenge. For instance, while most will "assume" box means a total containment container, the real definition does not indicate this description as the only one. We have all used boxes that were open to carry something elswhere. If such box were used here as I am not assuming an enclosed box, based on the original question, then the bomb goes kaboom and the stuff leaves the area but the box being made of indestructible material does not change in weight (Mass) however the question does not say whether to measure the box and related materials for the change in state. An open box will result in a different result than a closed box if we are looking for a difference in "system measurement" (box + stuff being "weighed " with box). If we are only, AGAIN NOT ASSUMING ANYTHING, looking for a change of only the box alone, which can be a possible interpretation of the question parameters, we will have the answer "No change in weight of the box after the bomb explodes" as it is indestructible and any measurement should be of the box alone, not any residue, pressures of gases, gamma rays, alph particles,... or what have you. Where and how, are we to measure the change? I trust someone out there has taken the time to thoroughly read this and analyse, hopefully logically, ignoring the occassional misspelling.

I think we need some more - non-radiative and isolated

I cannot agree. Indistractable does not mean "NON CONDUCTING" or "NOT PERMIABLE". If the box has a pin hole, the box is still can be indistrctable. Also there is no subtanse known with zero thermal conductivity. If I am wrong for the sake of all the participants please name the substance. If you cannot You have to agree that converted energy escaped and therefore the total mass is reduced.

Hi, zodiac!

Your understandable confusion is due to your belief that there cannot be such a box.

You are correct. But your objection is completely beside the point and not relevant to the question.

The point was not the box's construction. It was that the box imposed absolute limits on its contents, making it a theoretical box.

A theoretical box can be anything the designer wishes, including impermeable, indestructible, and so on. The construction and materials of such a box are supposition and imagination.

We don't even have to think about how the bomb got inside, or how it was exploded. It was just there and it just did. That's all. How did that happen? Simply, that the person who asked the question supposed it to be so. A universe was instantly created with rules outside the realm of our reasonable explanations.

In the universe of the bomb blowing up in the indestructible box, there are indestructible boxes with bombs blowing up in them. It's a natural phenomenon, like a big hollow electron with a bomb inside. The box has no molecular or atomic structure to make it permeable or malleable. It's a single entity, box-shaped, and imposes absolute limits on its contents.

When you attempt to place reason into its construction, you are writing about a different box than the one in the question.

Mark

Amen.

I agree and that's why I stand by my original conclusion.

Ken Leigh

Can someone please address my relativity question? I'm not suggesting there is anything wrong with the challenge question or the answer given, just to be clear.

It's just in reading it and thinking about it, I thought to myself "wow, a nuclear bomb confined to a box where the energy can't escape would get really, really hot. Hot, of course, simply means the random motion of particles. It occurred to me that it something got hot enough, it would mean that particles might be moving at relativistic speeds. If this were the case, would relativistic mass play a role. Just looking for some help here.

Hi, Roger Pink!

"wow, a nuclear bomb confined to a box where the energy can't escape would get really, really hot. Hot, of course, simply means the random motion of particles. It occurred to me that it something got hot enough, it would mean that particles might be moving at relativistic speeds."

The first law of thermodynamic states that "energy can be transformed (changed from one form to another), but it can neither be created nor destroyed". Let's examine how that applies to your query.

Maybe particles that had been transformed into energy via the chemical changes of the bomb would as energy (light, electromagnetic impulse) re-commence the movement at relativistic speeds that they had locked into potential energy when they slowed below those speeds [m=e/c²] at the point of manifestation so they could be manipulated as elements and made into a bomb.

As energy moving at relativistic speed, light and electromagnetic impulse could disturb the physical components, resulting in your "really hot" heated matter and gases. But although we think of "heat" as energy when we transfer it in thermodynamic equations, it really is only the result of energy that has been deliberately applied to matter acting on that matter to produce a change in vibrational speed, measured by temperature change.

No matter how hot an item got, until it changed into light and electromagnetic force, it couldn't move at relativistic speeds, which we have defined as being within the realm of energy styles alone (and the star ships Enterprise & Voyageur and the like: but they cheat by warping space).

Those changes can take place at certain temperatures, though. (Consider "red hot" shows some matter releasing the added energy in terms of light. It's not certain that the nature of the matter will always change in terms of lost mass, but certainly the manifestation of the matter is identifiable as releasing energy.)

That's why the first law applies, according to some in here (me included) when the changes take place within an impervious box. Whatever changes are going on in there stay there. However they are measured, they have to add up to an equation that balances before and after the explosion.

Mark

Ok, lets forget about the box, since it really doesn't matter to my question.

My question is Can a plasma get hot enough that it's particles move relativistically?

Hi, Roger Pink!

No, as I understand the definition of a plasma to be a charged gas. It exists firmly in the realm of matter. Otherwise, refer to my former answer to you about possible state changes involving particles at relativistic speeds within the realm of the first law.

Mark

Roger - the answer is not only that it can, but that they all do - it's just a matter of extent. In this particular case the proportions would be quite small, as only a small fraction of the total mass is converted to heat in a nuclear explosion. But it becomes very significant for the self-contained plasmas that are used in nuclear fusion.

For the time being, try looking at my post #140. If that is insufficient, please ask again.

Regards

Fyz

Fyz,

Thanks, I hadn't seen you're post #140 where you do in fact answer my question when you said:

"moving particles weigh more than stationary particles [m=m₀/√(1-v²/c²)]"

You know, the reason I was asking was because I am familiar with the concept of relativistic mass, but I had heard that it shouldn't be taken too seriously, so I was confused. I wasn't sure whether relativistic mass was just inertial or if it results in increased gravitational interaction as well. (I know relativity deteremined the equivalence between inertial and gravitational mass, still, I didn't know if relativistic mass was real or not). Here's a discussion on the matter which really doesn't clear things up for me:

http://www.advancedphysics.org/forum/showthread.php?t=5589

I would appreciate any insights you (or anyone else here) could provide.

Remarkable - everything written on that page appeared correct - albeit in one or two cases the only way you would be likely to understand what they meant would be to know it in advance.

As they stated, the effective mass of a single moving object depends on the frame of reference. The rest mass is a constant, and is the mass measured in its own frame of reference. In that sense, it can be misleading to take "relativistic mass" of a particle to have any sort of general applicability. The GR distortion of space-time equally depends on the frame of reference in which you observe it: the numbers relating to events and even the order in which the events occur can depend on the frame of reference, but the predictions of whether or not events occur and how they interact is independent of the frame of reference. I suppose that's just stating that the theory is self-consistent - like saying that it doesn't matter what frame of reference you choose to make your measurements in - they will transform to the identical values when transformed to any specific frame you choose.

. Now, to return to the plasma (or a spinning body, or indeed any system where elements move with respect to the centre of gravity). I'll word it as SR first: these systems have a "natural" frame of reference - that in which the centre of gravity of the system is stationary. If you measure the effective mass of the system in that frame of reference, you can call that the rest mass of the system. As the temperature (or rate of rotation, or element velocities) increase(s), the system's rest mass will increase. You can then use that rest mass to calculate the apparent mass in different frames of reference. What I am trying to say here is that the concept of "relativistic rest mass" does have this specific generalised meaning for a system.
. In terms of GR, the averages also work out to be almost exact. However the complexities of the internal distortions can have significant effects; in common with most GR effects, these distortions are more apparent with larger systems, which is why (for example) we observe decay in large binary star (or star+so-called_black-hole) systems.

I've just re-read what I have written, and it all appears quite clear to me - but I already know what I'm trying to say. The reality therefore is that it's probably ambiguous and misleading - so please take me up on anything that doesn't seem both clear and correct.

I think I understand (as long as by understand we both know I don't mean completely).

Now that I think about it, I do know that 1s and 2s orbitals (as well as higher energy shells) in an atom with a large nucleus (lets say lead) contract due to relativistic effects. I've thought of this as a consequence of lorentz contraction of space (which is fine). However it occurs to me that one could equally make the argument that the electron gaining "relativistic mass" could also equally explain the orbit contraction. I know this because I've done muon trapping calculations in molecules in the past and know that the muon's 1s shell is much closer radially to the nucleus than an electrons would be because it is so much heavier (I'm talking about muon minus like in Muonium).

I don't know, I understand a lot of it but much of it is still confusing to me at times. Often there is a give and take in relativity that balances everything out, except when you start think of the specifics, you can think of the give, but can't figure out the take. Thus you end up with what appears to be paradoxes that are in fact perfectly ok when all effects are included.

I just reread my post and I'm not sure that even I understand what I just wrote, sigh.

Are Bob D and EElectrician in agreement? The bird in the box, is same as energy in the box after the explosion. Within the box, will there ever be another explosion? What if the box, though indestructible, is clear, and lets light out, or lets light in?

Then would the passage of photons out, through the glass, perfect indestructible box change weight?

To me when taking a picture with a glass lensed camera that had a rating for how much it slowed light, something physical was always implied.

According to the discovery of the great real void, multi universes are implied, as if the great void is a box.

I like the Box idea, better than the Wall concept, though both of course exist, and are essentially the same difference.

Now I think of the Exosphere with the Krill in it that lived for at least 6 years. Is the dead Krill ever to come back to life? No. It will not, same as the explosion in the indestructible box.

All right. There are universes in boxes separated by great voids that are both large and small, long and short.

Light in some universes moves faster, than in others. Light in a slow light universe gets to its mass and collapses into the big black hole, same as it does in the fast light universe.

So then does the bird forever fly inside the box, at the same speed?

Do you create another universe whenever you slow light in a glass and burn up an ant?

I need to ask a Buddhist about this.

<< removes pot-stirring spoon from oneriness drawer >>

A few questions:

So for, most of the posts have discussed the bomb and the box. One, I think mentioned the possibility of the bomb being in a vacuum in the box.

What if gas is in the box? Won't the explosion create a shock wave? What affect will that have on the box? Won't the shock wave, or even particles from the bomb colliding with the insides of the box, create an audio frequency signal that travels through the box material, and it can be heard or detected by sensors? Wouldn't that take care of the issue of how to detect the explosion?

Then issues come up concerning the nature of the gas. What if it is normal air (earth atmosphere)? What if it is an inert gas? What if it were a reactive gas, such as oxygen or nitrogen? What if it were radon, which is radioactive? What would be the effects of the explosion on these various types of gases?

What if the box were filled with a liquid?

What is the position of the bomb in the box? If the center of mass of the bomb is in the exact same position as the CM of the of the box? How is it supported in this position? Tractor beam? Magnetic levitation? Pedestal? If it is supported by maglev devices or a pedestal, what effect does this extra mass have on the outcome? If the bomb is sitting on the bottom, won't that affect energy/mass distribution? What if the bomb was on the bottom, but next to one of the sides?

<< puts pot-stirring spoon back in oneriness drawer. contemplates investing in pharmaceutical companies because of headaches created by questions. >>

Does it matter what's inside the box other than the bomb? I mean, if there's only the bomb, the ultra-fast shrapnel will hit the inside of box; if there's a gas or fluid inside, the shock wave will hit the box. Either way, whether you can detect the explosion depends on the properties of the box.

Now, if you can tell that the bomb has exploded, that means that a wave carrying information (and associated energy) has left the box. So the box will be lighter by an appropriate amount. Of course you could heat the box in some other way to compensate....

That Schroedinger's Del gets everywhere.

What about energy that can get mvoe throught the box material. Like heat energy. ??

I don't get it. Shouldn't the energy disipate as heat, sound, etc. The box may be indestructible, but it conducts heat, isn't it?

Hi, Guest!

Your answer is in the rules. The box is indestructible. Does it 'give off' anything? Not according to the challenge. Impervious. No heat, no light, no sound, no energy leaves. Box doesn't change size or shape. Box doesn't absorb or reflect. Box just is. Box contains.

Box is imaginary, invented for the purpose of the challenge, with imaginary A-bomb also invented for the same purpose about to go off already inside the box when it was created. Bomb not put there in some fashion. Bomb not set off by anyone on the outside (or inside). Just is there. Just goes off.

Everyone knows that when an A-bomb goes off, all kinds of changes take place in the bomb. Now, they take place in a container that absolutely can't lose anything regardless of those changes.

The OP asks whether the box will lose any weight when the changes take place inside it.

Mark

Are you equating "indestructible" with "impervious".

Taking an absolutist view in linguistic meaning, I'd say "absolutely impervious" would have to imply indestructible, but not the other way around. Physically, of course, neither is possible (sorry, Schroedinger and Del), so absolutist physical arguments are somewhat dubious.

However, we could take it that in this context "indestructible" simply means that the container is not destroyed by the nuclear blast; such a container is indeed possible (subterranean nuclear explosions could be examples?) - and a physical one would certainly radiate, even if it didn't conduct.

So, the challenge may be ambiguous - but the closest possible physical situations are not; being a 'umble hexperimentalist, that's good enough for me.

Indistratable does not mean that it is not non-permiable or thermally non conductive. Even if you take one by-product of explosion, say heat, the energy will be transfered from the inner surface of the box to the outer by conduction and from there will be dissipated. Therefore the box with its content (Bomb) will weigh less.

Hi, Guest!

You are perfectly correct.

As long as we're discussing your box. However, yours is...apparently...not the same type of box as the challenge questioner's box, which, given its definition within the answer, is also correct. In this instance, you are both correct.

There are all kinds of boxes out there, and depending upon your definition of your box, you are entitled to correctness as you describe all its properties.

Therefore, everyone who has postulated a box that is likely to fit within the parameters of "indestructible" according to his own definition and describes attributes to it is unerringly correct.

In honour of all of these definers of their own fictitious boxes (including the one in the challenge question), I would like to add two more definitions of my own.

The first is a box composed of a material called "more-ium" that while being indestructible, sucks energy from the universe every time an atomic bomb goes off inside it. There is no question in my mind that, having had this occur at least once during the time period alluded to in the question, the box will be heavier after the explosion.

The second box, which as you will see has some notoriety, is called the "fish whistler", and is only found underwater. Every time an atomic bomb goes off in it, it turns blue and whistles. This causes it to weigh less. However, the colour and sound attract box fish, which fasten themselves to it permanently, and die. So, after the initial effect, the box weighs more. Thus, the "fish whistler" box has the unusual quality of weighing both less and more after the explosion.

Interestingly, even if the fish whistler box were to be constructed of more-ium, since the mass of the fish is considerably less than that of more-ium, the post-explosion box will have a total mass less than pre-explosion even though it weighs more.

The resulting 'fish whistler box mass calculation' can become complicated if the box is resting on the rocky bottom of the body of water in which it is located, since the box fish cannot attach themselves there, and the decreased mass will only occur on seven of its eight sides. Physicists have referred to this calculation difficulty as the 'fish whistler box mass rock side calc. mess'.

A calculation was derived for it by a 19th century German physicist named Hershel Knish, who postulated that the eighth side should be considered equally fished and the results deducted from the total mass. He has since been repudiated. See Wikipedia "Hersh Knish's fish whistler box decreased mass rock side calc. mess minus eighth side error foible" and the repudiation by the noted Papua New Guinea atomic physicist Ernst Frizzle. This caused quite an uproar in the physics community and you can find a front page headline about it in the PNG Times: "Ernst Frizzle's Failing Hersh Knish's Fish Whistler Box Decreased Mass Rock Side Calc. Mess Minus Eighth Side Solution Error Foible For Feasibility Causes Physics Fracas. [story on page 2]"

There is, however, a brush: the "fish whistler box bristle brush", which is designed to clean the dead box fish off the box, making it weigh less again. And, if the fish whistler box bristle brush comes with an attached bottle --the fish whistler box bristle brush bottle-- and that bottle is filled with more-ium box refinish [fish whistler box bristle brush bottled frazzled box re-finisher], it can make the box weigh the same as or even more than its original weight depending upon how much re-finisher is applied, using a technique called 'fish whistler box bristle brush bottled frazzled box re-finisher finite refurbishment'.

Mark

^{"Fox in socks, our game is done, sir.
Thank you for a lot of fun, sir."}

Right-on, Humpty Dumpty, you've made your point - "when I" (= the challenger?) "use a word, it means just what I choose it to mean -- neither more, nor less".
Now, was I imagining it, or did you promise to pay your words extra when you work them like that? Oh, and please be careful sitting on that wall box of yours, lest it leaks in spite of what you decided indestructible meant. (All the king's hearses and all the king's men are not equipped to cure radiation sickness)

Alice

Hi, Physicist?

Ah yes, but my radiation comes from a type of atomic bomb made entirely from carrots, and is not only healthy for you, but leaves you with wicked eyesight!

Trouble is, this type of A-bomb_C is only found in indestructible boxes, so nobody can ever get at it (cute joke--leaking box).

We only know about the eyesight thing through theoretical calculations done in underground carrot labs (where else would you situate a carrot lab?) where a variety of carrots known to be high in carrotonium are accelerated through giant juicerators several kilometers in length to nearly the speed of light; plus the statistical evidence gained by examination of a series of janitors who have worked there and whose eyesight was noticed to have improved exponentially during their terms of employment, and may have had something to do with the environment of their office and routine, which was juxtaposed to the accelerator in some way that required them to jump over peripheral piping in order to get at the mop closet.

I believe the article examining the statistical evidence in Carrot Physics Journal was "Giant Juicerator Janitors...something or other...". Sorry, I just can't recall the whole thing.

Mark

Love the vitamin-A bomb. Did all your janitors return, or did some of them suffer the same fate as Scott and Oates?

I understand that it's not just vit-A either - these juicerators have been known to release high-energy beta-caroteneum particles that bypass the usual saturation effects; paradoxically, one of the earliest observed toxic effects can be blindness.