[CliffordK]

William,

Are you denying the existence of atomic bombs, or that two were dropped on Japan at the end of WWII?

Fat Man, a relatively small atomic bomb by today's standards weighed just over 5 tons, with a blast yield of about 21,000 tons of TNT.

Little Boy weighed a little under 5 tons, with a blast yield of about 16,000 tons of TNT.

Little Boy was detonated at about 1,968 feet, and destroyed buildings in about a 2 mile diameter circle, killing about 66,000 people, and injuring another 69,000 people, and potentially leading to 200,000 fatalities. 

There is no conventional bomb weighing about 5 tons that could come close to that amount of destruction.

Your article above suggested that gasoline (or various oils) have a higher explosive content than TNT.  While that may be true, the caveat is that petroleum fuels require a stoichiometric ratio of an oxidizer (air) to be compressed and detonated with the fuel.  It is not sufficient to squirt hot oil into the air, but for an explosion, both the fuel and oxidizer must be compressed.  Explosives such as TNT or nitroglycerin do not require an additional oxidizer.  Likewise solid rocket fuels also include their own oxidizer as they must perform at high altitude where air is not readily available.  Keep in mind the LEO/GER oxidation/reduction reactions may be considered oxidation with other elements behaving similarly to oxygen.

So, consider two explosives.
A stick of dynamite immersed in a 5 gallons of oil, encased in heavy metal such as a propane tank with no trapped air.
A stick of dynamite encased in a tight fitting steel pipe.

The dynamite in the oil will not have sufficient oxidizer available, and will be no more powerful than the dynamite in the pipe.  In fact, the oil bath might absorb some of the blast, lowering the overall blast content.  The oil, of course, might burn causing a secondary fire, but not explosion.

As far as back to the topic with heat.
You may wish to read about Planck's Law..  Hot objects will emit light with a peak intensity at a wavelength corresponding to the temperature, but will emit that light over  many wavelengths.  Objects on Earth with temperatures between 0°C and say 40°C will emit light in the infrared range. 

The sun with a much hotter temperature, around 5500°C will also emit some IR, but its peak intensity is with much shorter wavelength EM, in the middle of the visible light spectrum.

[bizerl (OP)]

The original question was raised in regards to heat applied at one end of a material, affecting the other end. I was interested in how that happens. Thanks for all those who answered. The turn taken by the "conversation"  has raised another question, relating to this.

Obviously a nuclear explosion makes a vast amount of matter very, very hot very, very quickly. So is this the "thermal diffusion" of air working really well?, or just the incredibly hot reaction? It seems to me if it was placed in even something like diamond (which seemed to be the best thermal conductor), the heat would not radiate as quickly as in air.

Also, when you guys say "light", do you mean "electro-magnetic radiation"? I was led to believe that all light is electro-magnetic radiation, but not all electro-magnetic radiation is actually light.

In terms of heat vs infrared, I always thought that the effect of IR was heating (like a microwave), but that heating could occur without IR as well. The discussion has now made me think that perhaps IR is the expression of a transference of energy, which is felt by us as heat.

I have no links or formulas to back up anything I have said, just the musings of a curious mind.

[CliffordK]

Here is a list of thermal conductivities.  I didn't realize that Diamond was so high up on the list.  Aluminum or Copper are quite high, but much lower than the diamond.  Silica aerogel is near the bottom for thermal conduction, at least for solids.



Vacuum Thermoses, of course, use use the lack of conduction/convection through a vacuum to keep their contents hot.

All light is Electromagnetic Radiation (EM), or photons.  However, the EM spectrum covers a range of wavelengths.  It is essentially the same as light, but we define different ranges of wavelengths from high energy gamma rays to x-rays to UV to visible light to IR to microwaves to radiowaves (which can have wavelengths of several feet or more).  Our eyes are only sensitive to a narrow band of the "visible light".

So, if you think of a hot electric stove burner.  If you touched a diamond, or a piece of copper or aluminum to the hot stove burner, the conduction would be fast and hot. 

If you held your hand a foot above the stove burner, you would have slower conduction of heat through the air to your hand (conduction & convection), although the surrounding air would eventually be warmed which you would feel when you would put your hand near the burner.  As well as the hand being heated by infrared (or red) heat radiant heat.  But, the transfer of heat through the air is slow, so you wouldn't want to suspend your kettle even a few inches above the electric burner.

A piece of glass (or double-paned glass) above the burner might block the convection/conduction heat and you would be left with pure radiative heat.

Note, you can have a steel kettle with a steel handle, and not get burned (too badly at least).  But, a copper kettle with a copper handle would get the handle too hot too quickly, and transfer that thermal energy to your hand too quickly.  Copper or aluminum cookware, however, is good for even heat distribution.

I did try soldering/welding silver once.  It was a pain because of the rapid heat conduction throughout the whole piece.

[William McCormick]

My father worked at Grumman Aero Space. T

Sorry I did not get back to you sooner I was welding up a set of railings for a friend. I made some shop drawings about three weeks ago, and bent it up two weekends ago, and yesterday and today between doing laundry, I welded them up. Now it is back to work tomorrow, Ahhhhhh. 

                      Sincerely,

                            William McCormick

My mum taught on of the Spice girls and, like you dad's job, that also has absolutely nothing to do with the issue.

Unless your dad was using the word arc before My Davy, he's misusing it.

Nice railing.
It must be a right pain in the neck doing all that cutting to 6 digit accuracy. Do you have your own interferometer to check the pieces?
Also, how good is your air conditioning?
I find that temperature changes of just 1 degree alter the lengths of bits of steel by 15 parts in a million or so and Aluminium is even worse.

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

Damocles, I just wondered, given that William had struggled with it. He seems not to have understood much of it.

That is actually to three digits iof accuracy, Or thousands of an inch. It is the default of the cadd drawing program.

I can output those to 1/16ths or even 1/32ths of an inch about all that is practicle. But the truth is that our tape measures are in 16ths of an inch, so we hardly ever practice 1/32ths. So hearing 11/32ths kind of throws us.

But having always done machining we are familiar with thousandths of an inch and where they fit within 16ths of an inch. So I just convert the hundredths place, to a spot within the 1/16 mark. There are aproximately six hundredths of an inch between sixteenths of an inch.

But another reason the three places are a good default is that if you are making a spacer to put between pieces you are placing, you will need accuracy to thousandths of an inch.

Myself and an Austrlian fellow created the macro that automatically measures each section within a concatinated line. So I just touch the line and it places those measurements at each break point. So I can lay out the marks on the pipe while it is straight. It takes me 30 minutes to draw the pipe rail and stoop. 30 minutes to bend the pipe. And then about eight hours to fabricate. Without the macro and drawing. It would take me two or more hours to lay it out and the two railings would never match so exactly. So it is just for speed ease and accuracy I do it that way.

I knew Roy Grumman, met him when I was 1 1/2 years old. He got down lower then me and looked up at me, gave me a real mans hand shake and welcomed me to the plant. He used to pay for family picnics that were pretty cool.

We had the technology to go anywhere, but slavery and the price of real estate do not profit from a real space program. So they cancelled any hope of it.

Sending this from my iPhone, please excuse typos.


                             Sincerely,


                                William McCormick

[Bored chemist]

OK, so now we know that you can't even count.
104.372 has 6 digits (and 3 places of decimals).

"When you release 7,600,000 BTU's in a fraction of a second, you get a blast, like the one at Hiroshima. "
Nope, you get about ^ J or about 2 tons of TNT equivalent.
It would make roughly as much mess as a V2 rocket did (That was 1 ton so 7,600,000 BTU would give a slightly bigger crater if it was released suddenly enough).
It would take out a few buildings, but it wouldn't demolish a good chunk of a city.

Hiroshima was not a ton of oil catching fire.
This is the effect of 300 tonnes of petrol , largely premixed with air catching fire and progressing from a deflagration to a detonation.
http://en.wikipedia.org/wiki/2005_Hertfordshire_Oil_Storage_Terminal_fire

Death toll nil.

To say that the bomb dropped on Hiroshima was 300 times less mass of a fuel which doesn't explode readily is not only absurd, but an insult to those who died there .
I'm happy to excuse the typos, but I find it very hard to excuse your delusional ramblings.

[JP]

Modnote:
Ok guys, let's keep it science, as per forum policy.  We'll step in and moderate the discussion if it gets too far off topic, especially if it tends toward conspiracy theories.

[alimeeabey]

Silicon is semiconductor material. Due to its good heat transfer properties, it has huge application in the aluminum and steel industry and uses large amounts of silicon in alloys. The rate of heat transfer is dependent on the temperatures of the systems and the properties of the medium through which the heat is transferred. But its main application is in Semiconductor industry as silicon wafer used in various microprocessor devices.