How to calculate the size of an explosion?

  • Thread starter Buckwheat Jones
  • Start date
  • Tags
    Explosion
In summary, the conversation revolved around determining the size and source of a cloud in a photograph of a jet crash. It was estimated that the cloud was approximately 600-800 meters wide and formed by the explosion of 10,000 gallons of jet fuel. The experts suggested calculating the volume of vapor produced by vaporizing the fuel and taking into account weather conditions and convective currents. The conversation also touched on the possibility of the photograph being manipulated and a conspiracy theory surrounding the event.
  • #1
Buckwheat Jones
4
0
I'm studying a photo of a jet crash and it's subsequent cloud plume. I'm calculating that the cloud is 1000 meters wide and 7-800 meters tall, with the altitude of the cloud hitting maybe 900-1000 meters.

Is there anyway to determine if this cloud is too big to have been made by a 757 carrying approx. 9-10,000 gallons (not pounds) of jetfuel? If not, what amount of TNT might produce such a cloud?

Any help at all would be appreciated. Thank you for your time.
 
Physics news on Phys.org
  • #2
Well the simplest way would be to calculate the volume of the vapor produced by vaporizing 10,000 gallons of jet fuel. Ignition (combustion) would probably increase that volume by about an order of magnitude, just by converting one molcule of dodecane (or naphthalene) to CO2 and H2O, even without the thermal energy released.
 
  • #3
Calculating explosion

Thanks for responding, but have to tell you that I've got no idea how to do this. I'm not a student of physics, I just came on here figuring I'd ask people who knew more about these things than I did. Is there a layman's way to calculate this?

Thanks for your time.
 
  • #4
800 meters? No airplane crash or conventional bomb alone will produce a cloud 800 meters across.

How high or far a continuous fire's smoke will go is mostly a matter of weather.
 
Last edited:
  • #5
Russ beat me to it. What was the weather like? What kind of winds were in the area? Convective currents could have carried to top of the plume to very high heights which has nothing to do with the source.
 
  • #6
Well, here's what I'm trying to determine. A photograph was taken of Flight 93's mushroom cloud, and you'll see it here:

http://www.talkingproud.us/ImagesEagle/AttacksonUS/Shanksville.jpg [Broken]

There seems to be some discussion about whether or not this image is real or a crock. As a professional image retoucher (Photoshop as a day job), I know that pasting in a cloud on a clear blue sky is virtually impossible to pull of seamlessly. However, I cannot inspect the master file so I have to ask questions based on other known quantities:

1. The plane may have had approximately 10,000 gallons of fuel on board as it was a cross country flight, and it carried a capacity for 11,500 gallons.

2. The point at which the photo was taken is a known, the crash site is a known, so the distance between the two is known. So by graphing out a pair of vectors originating from the camera, to the edges of the cloud (using the two barns on either side of the cloud as reference points,) the cloud seems to be about 600-800 meters wide, if you account for a little wind and intertia from the blast moving the cloud southeasterly by the time the photo was taken.

(See the Google Earth jpg here:http://photos1.blogger.com/blogger/7508/1605/1600/shanks-plume-1000ft.gif)

So, I'm trying to determine if 10,000 gallons of jet fuel could blow up and form a cloud this big. I thought physicists might offer some sound ideas.

By the way...would that be Fred Garvin...Male Prostitute?
 
Last edited by a moderator:
  • #7
If you'll notice the plume of hot air, 'bout 1/4 the width of the cloud rising vertically from the ground to the cloud, you'll deduce that not all the fuel went to producing black smoke --- there's a nice hot fire on the ground behind the trees.
 
  • #8
Bystander said:
If you'll notice the plume of hot air, 'bout 1/4 the width of the cloud rising vertically from the ground to the cloud, you'll deduce that not all the fuel went to producing black smoke --- there's a nice hot fire on the ground behind the trees.

I'm not sure I'm following you. You can tell there's hot air rising from a fire onthe ground, behind the trees, from the shape of the bottom of the cloud?
 
  • #9
The small white structure in the center of the picture --- there's a narrow plume of smoke directly above it --- that plume is just within the right-hand boundary of the hot air plume. The "notch" in the tree line above the white structure --- move to the high point on the left --- one cursor width to the left of that is the left hand boundary of the hot air plume. It remains at constant width all the way up and through the black cloud to the top of the picture.

Is it a "large" cloud for 10k gal.? No.
 
  • #10
Good enough.

Sorry, Buckwheat Jones, we don't entertain conspiracy theory here.
 

1. How is the size of an explosion measured?

The size of an explosion is typically measured by the amount of energy released. This is often reported in joules (J) or equivalent units such as tons of TNT.

2. What factors determine the size of an explosion?

The size of an explosion is determined by several factors, including the amount and type of explosive material, the confinement of the explosion, and the environment in which it occurs.

3. How do you calculate the size of an explosion?

The size of an explosion can be calculated using the formula E=1/2 x m x v^2, where E is the energy of the explosion, m is the mass of the explosive material, and v is the velocity of the explosion.

4. Can the size of an explosion be predicted?

While the exact size of an explosion cannot be predicted with complete accuracy, scientists can use mathematical models and simulations to estimate the potential size of an explosion based on the factors mentioned above.

5. What is the largest explosion ever recorded?

The largest explosion ever recorded was the detonation of the Tsar Bomba in 1961 by the Soviet Union. It released an estimated 50 megatons of energy, equivalent to 50 million tons of TNT.

Back
Top