Talk:TNT equivalent

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See also Talk:Tonne of TNT for old discussions.

Why TNT?[edit]

Can someone add a history section how TNT come to be used as the standard. —Preceding unsigned comment added by SweBrainz (talkcontribs) 5 Nov 2006

Consolidation[edit]

Last night I merged Tonne of TNT and material from Ton here, since there was a lot of redundant content. I also re-redirected kiloton and a number of similar redirects to point at ton and not here, since they are often used to speak of mass rather than explosions. I don't claim to have done this perfectly, so please be bold in following up on it. I didn't see any existing controversy over this terms, but if I have created one, I'm willing to discuss. --Strait 17:17, 7 February 2007 (UTC)

Part of what I'd put in section below moved up here Gene Nygaard 03:50, 8 February 2007 (UTC)
I'd also like to discuss your related moves, such as changing megaton to a redirect to ton after that was expanded and also linked to this newly expanded article as a "Main article". While I think that has some good points, there are factors that need to be discussed.
For one thing, the various moves have left an orphaned talk page without an associated article, which I linked to at the top of this page.
For another thing, right or wrong, the "megaton" article dealt primarily with energy equivalent of TNT. (Note that after your moves, we need to go to the history of the redirect at "Tonne of TNT" here to see what it said.) The "ton" article deals primarily with mass, but also many other meanings of the highly ambiguous word. But most of the links to "megaton" were to the TNT equivalent meaning.
Those links should all be cleaned up. Not only to link to a more specific article, but also to specify the units, in the visible text in the articles containing those links, as "tons of TNT" or something of the sort, not just "tons" and "kilotons" and "megatons" as if they were units of mass rather than energy.
One of the problems is that if people are talking about wheat production, for example, they rarely use "megatons". Those mass units usually "million tons" or "million metric tons" or "million tonnes" or "million metric tons" in that context. And even if the tons are not identified as metric tons in that context, they almost always are—because even in the U.S. metric tons are the only tons in general use for that purpose. When these numbers are not expressed in metric tons in the United States, they are not expressed in short tons either, but rather in bushels as units of mass, with 1 bushel of wheat or soybeans ≡ 0.0272155422 (metric) ton, 1 bu of corn or rye ≡ 0.02540117272 metric ton, 1 bu of barley ≡ 0.02177243376 metric ton, etc.
Another is that nobody talks about "short megatons" or "long megatons"; megatons (even if not dealing with energy) are almost always metric tons. But a large part of the "ton" article deals with all the various distinctions between long, short, and metric tons not only in the mass units and the force units, but sometimes in energy or power units or whatever. Gene Nygaard 19:39, 7 February 2007 (UTC)
Although in "The Los Alomos Primer - The first lectures on how to build an atomic bomb", original declassified document uses short tons, and Serber even explicitly says it's 907kilograms. Which is it?
Currently a megaton explosive is defined to be exactly 4.184 gigajoules (see opening paragraph). That makes any squabbling over the original ton meant irrelevant; it is now a unit of energy, no longer one of mass. Whether it was originally long, short, metric or simple is not longer meaningful. SkoreKeep (talk) 08:00, 5 March 2014 (UTC)

contradiction[edit]

Gene Nygaard: You removed the contradiction tag from the "values" section. I was not confused about the meaning of "convention". Here I have highlighted the problem:

A gram of TNT releases 980–1100 calories upon explosion. To define the tonne of TNT, this was arbitrarily standardized to 1000 calories = 1 gram TNT.
This definition is a conventional one. Explosives energy is normally calculated using the thermodynamic work energy of detonation, which for TNT has been accurately measured at 1120 cal/g from large numbers of air blast experiments and theoretically calculated to be 1160 cal/g.

Not only does the second figure fall outside of the range of the first, but the first figure implies that the value is either inconsistent or poorly measured, whereas the second does not. --Strait 17:24, 7 February 2007 (UTC)

That says, to me at least (but maybe just because I know that, and the wording may need to be tweaked), that the term "ton of TNT equivalent" always means a gigacalorie, derived from a conventional value of 1000 cal/g times a million grams. It doesn't matter what the actual energy TNT produces. But the article tries to explain that in one way of measuring that, it is higher than the conventional value, and that in another way of measuring it, it is lower than the conventional value used to define a "ton of TNT equivalent". The problem may be that not everyone will understand what the word "conventional" means in this context, so the transition to measurements made in different ways needs to be made more clear. [part moved up, re-signed here Gene Nygaard 03:50, 8 February 2007 (UTC)]

It appears that there is an error in the section about Blast Radii and the  R = \left( \frac{E t^2}{\rho} \right)^{\begin{matrix}\frac{1}{5}\end{matrix} } equation. It's stated that G.I. Taylor arrived at a figure of 22 kilotons for the yield of the Trinity device based on a 140m fireball radius at 0.025 seconds into the explosion. However, when I ran the equation myself today (just an exercise in keeping the mind healthy) my result was closer to the officially stated yield of 20 kilotons than the 22 kiloton figure.

The equation I used was a transformation of the above equation to solve for E -  E = \frac{R^5 \rho}{t^2} - which, unless every math teacher I had in school a decade ago are wrong - is correct. I came up with a figure of approximately  8.6 \times 10^{13} Joules, or about 20.6 kilotons. The difference could very likely be that the article speaks in terms of "approximately  9 \times 10^{13} Joules, which is about 22 kilotons when rounded to the nearest integer.

I wouldn't be complaining about it, but the way the article is written makes it sound like either:

  1. The officially stated yield of the Trinity test device is incorrect …or…
  2. The equation is not actually accurate.

Since I solved the equation myself and have seen that the result matches the official number to within 3% I'm certain that both of the above are false. The official number is likely a truncation of the known yield for ease of public consumption and the approximate 20.6 kiloton figure returned by solving the equation is probably the real yield figure.

As this is an article about a subject I have only a passing familiarity with I do not feel qualified to make an edit to the page, nor I am sure how to note that the stated 22kiloton result (and hence the approximately 10% level of error in the figure) is a result of the rounding done and not a result of the equation being inaccurate. And I'm also not sure if such should be done. - An anonymous Wikipedia user

Chixculub[edit]

The one that killed off (most) dinos might be added to the list. Values should be around. Dysmorodrepanis (talk) 03:54, 26 March 2008 (UTC)

What ton[edit]

GNU units uses the short ton rather than the tonne - is this just to allow notation like "kiloton" to come out right, or is it actually based on 1e9 cal/shortton ? --Random832 (contribs) 17:43, 27 June 2008 (UTC)

I'm fairly sure that the ton (that is short ton) is correct and the tonne (metric ton) is incorrect. That is, the definition should be 1e9 cal/short ton as you say. This is backed up by http://physics.nist.gov/Pubs/SP811/appenB8.html, one of the references given in the article. It's pretty clear from context that when that page says in its table that one "ton of TNT (energy equivalent)" is "4.184E+09 joule (J)" it means a short ton, not a metric ton.

This means that all the claims of the form "1 gram TNT = 4184 J (exactly).[2]" in the article are incorrect. They're off by about 10% since that's about the difference between a short ton and a metric ton. When you take this into account, I believe the correct statements are: 1 (short) ton TNT is 4.184 GJ (exactly) and 1 (metric) tonne TNT is approximately 4.612 GJ. 50.136.242.240 (talk) 07:25, 10 April 2013 (UTC)

Moreso, since the "megaton" is defined as 4.184 Mj, the megatontntequivalent is now a unit of energy, no longer one of mass (at least this one is so), so wondering which ton of TNT was originally meant is no longer relevant. SkoreKeep (talk) 08:06, 5 March 2014 (UTC)
Of course it's relevant. Every topic has a history. It's just helpful to remember the distinction between the original meaning and the current definition. The meter has been redefined quite a few times, but each of those older definitions is still relevant. Zyxwv99 (talk) 23:21, 12 July 2014 (UTC)
OK, pardon my obtuseness. You're right, historically it is relevant, though obsolete for purposes of current definition. I stand corrected. SkoreKeep (talk) 22:00, 16 July 2014 (UTC)

Heating value[edit]

Does anyone understand the 651 cal/g number cited in the page? I asked the author of the reference for a citation and an explanation. He replied, but he provided neither. I provided him with the following reference, which puts the TNT energy value (heating value) at 3575 cal/g, and the detonation energy at 1093 cal/g. The 651 cal/g certainly looks bogus. http://www.osti.gov/energycitations/servlets/purl/3648-Pc0V6C/native/3648.PDF In particular the above says "An explosion energy of 3575 Cal/g was measured by calorimetric methods-in agreement with thermodynamic equilibrium calculations of the “Heat of Combustion” for TNT (based on the CHEETAH code [55]). Thus, the explosion-induced mixing of the TNT products with oxygen deposited an additional 2482 Cal/g of exothermic energy as a consequence of the turbulent combustion process. In the popular literature, this is known as “after-burning” in TNT explosions (see Dewey [56])." —Preceding unsigned comment added by Jqwilliams007 (talkcontribs) 22:24, 4 September 2008 (UTC)


destruction power[edit]

how many miles would a certian amount of tons destroy? is it exponential? i was watching stargate and the mark IX was said to destroy everything within 100 miles, so how many mega/gigatons of tnt is that? —Preceding unsigned comment added by Beyblayde (talkcontribs) 23:14, 25 January 2009 (UTC)

Use the blast equations in the free book The effects of nuclear weapons, it takes some re-reading of sections but the equations will solve your thought experiment, and it really is determined by what you mean by destroy everything as that could be interpreted to mean everything would be within the fireball, or perhaps interpreted that they meant it would destroy all common brick houses and so on with blast to the radius.Boundarylayer (talk) 12:50, 4 March 2013 (UTC)

The Marot Hotel[edit]

As I was on the sidwalk at approx 300 to 500 ft when they bombed the Mariot in Islamabad,I wish to know more about that bomb.

robert-arcand@videotron.ca

Useful Reference[edit]

I was surprised to see that this page takes the point of view that the "ton" in kiloton is a "tonne". I do not think this is agreed upon or even, in my experience, very common.

A different point of view is expressed for example in the book "Explosive Shocks in Air" second edition, by Kinney and Graham, where it is stated on page 2 that the standard is 1100 cal/gram based on the "standard ton".

A footnote at the bottom of page 13 of "The Effects of Nuclear Weapons" at

http://www.princeton.edu/sgs/publications/articles/effects/effects-1.pdf

is worth reading. It points out that the kiloton is only a measure of energy, and the relationship between mass and energy is left ambiguous. It might be better to state this rather than take one particular point of view. Stevur (talk) 21:20, 13 August 2009 (UTC)

Dubious example[edit]

Something seems a little odd about this following paragraph from the examples section:

1 megaton, when converted to kilowatt-hours, produces enough energy to power the average American household (in the year 2007) for 103,474 Years. For example, the estimated upper limit blast power of the Tunguska event could power the aforementioned home for just over 3,104,226 years. To put that in perspective: the blast energy could power the entire United States for 9.5 years (based on average total energy use in America in 2006).

If something is sufficient to power the "average household" for 3,104,226 years, and could power the entire United States for 9.5 years, than a quick arithmetic check says that this means there are 326761 households in the USA, and that is assuming no other energy is used outside of these households. I'd suggest one of (or all of) the figures is incorrect... --Nick Moss (talk) 12:31, 30 September 2009 (UTC)

Yes, this was my first thought when I read that paragraph. There are definitely more than 325k households in the U.S. If I remember correctly, the number is close to 100,000,000. There are over 300,000,000 total U.S. citizens and I'm fairly certain that the average household size is substantially smaller than 1,000 people. 170.215.121.70 (talk) 21:14, 21 October 2009 (UTC)

I changed it to 3.27 days based on the statistics given in the CIA World Factbook. --Suffusion of Yellow (talk) 00:44, 22 October 2009 (UTC)

Unless someone cites actual numbers for the 2013 Russian meteor, I think that 500 kiloton claim needs to be removed. I think a 10 ton rock would have to be moving at 600,000 meters per second to get that amount of energy. I've removed the example. Hmoulding (talk) 05:35, 19 February 2013 (UTC)

Citation Needed[edit]

"4.184 petajoules[citation needed]" What fucking retard put that there? Seriously, what the fuck is wrong with wikipedia? You aren't even allowed to apply a simple conversion factor without needing a citation? Epic fail, wikipedia. Somebody ban me for this so I'm not tempted to waste my time trying to fix this type of bullshit.--Kickflipthecat (talk) 18:55, 21 November 2009 (UTC)

Dynamite vs TNT[edit]

Dynamite, for example, has more than 60% more energy density (approximately 7.5 MJ/kg, compared to 4.6 MJ/kg for TNT).

This is misleading; commercial dynamites have energy yields in the range presented for TNT - follow the links on http://www.dynonobel.com/dynonobelcom/en/global/productsandservices/northamerica/Products+%28march2006%29/Dynamite/ Since the quoted sentence isn't particularly relevant it might be simplest to delete it. 74.99.163.15 (talk) 19:04, 5 March 2010 (UTC)

Antimatter[edit]

I don't think using total conversion of mater to energy as an example is useful. It has nothing to do with TNT equivalent where a chemical reaction takes place, while matter+antimatter would be a change on the nuclear level. Also it's not TNT specific. I'd rather remove it. --Bur (talk) 15:22, 13 December 2010 (UTC)

Energy in Joules may need correction[edit]

Looks like the Joule value for kT and MT are wrong. A gallon of gasoline is equivalent to 130 MJ. The TJ values for the kT yields seem wrong. This is the source, http://www.evworld.com/library/energy_numbers.pdf which puts the Hiroshima yeild at 10^14 Joules. I think numbers here and in the Fatman and Little Boy sections need correcting. Possibly elsewhere. —Preceding unsigned comment added by 173.11.111.213 (talk) 04:23, 4 January 2011 (UTC)

Merge Discussion[edit]

I recommend that Exaton, Gigaton, Petaton, and Teraton all be merged here, for the same reason as Kiloton. I'm also going to recommend that Megaton be changed back to a redirect to this page, as it is overwhelmingly used to refer to the unit of energy. Nick Number (talk) 21:19, 2 June 2011 (UTC)

Earth example[edit]

In my opinion, the example given there is exaggerated. Supernovae are atomic explosions where a fraction of the star's mass is annihilated. Of course this mass is far larger than the size of Earth, so an explosion of the same size requires far more TNT. E.M. Balli — Preceding unsigned comment added by 78.172.211.216 (talk) 17:37, 12 June 2012 (UTC)

It is accurate to within an order of magnitude to say that 1044J is equivalent to 1028 megatons of TNT equivalent. However, it is wrong to say that such an amount of TNT would have a mass a mere 1⅔ the mass of the earth. 1028 megatons is 1037 kilograms. The earth has a mass of 5.9735*1024 kilograms. Therefore, the mass of the TNT equivalent to a 1044J supernova would be about equal to 1 trillion, 1012, earths. I edited it to reflect this. — Preceding unsigned comment added by Zork283 (talkcontribs) 16:57, 30 August 2012 (UTC)

Explanation on how many dynamites there are of 22 kilotons[edit]

how many dynamites are 22 kilotons?

reference to the fat boy nuclear bomb obviously here — Preceding unsigned comment added by 77.53.219.248 (talk) 05:22, 28 February 2013 (UTC)