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Why scale models are ineffective

1337m4n

Alphanumeric Anonymous Stick Man
1337m4n
Joined
May 10, 2007
Messages
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You may have seen a number of Truthers try to make scale-models of the World Trade Center and use them to "prove" that the towers couldn't possibly have collapsed. Famous examples include Richard Gage with his cardboard boxes, and Heiwa with his pizza boxes and his (fake) $1 mil challenge.

These don't work. Read and learn this article about the Square-Cube Law.

Did you read it? No you didn't. Stop trying to skip ahead. Read it, I say!

Okay now. If you magically double the dimensions of a tower, its weight will increase by a factor of eight, but the structure's load-bearing capacity will only increase by a factor of four.

This works in reverse, too--if you magically shrink the tower's dimensions by half, its weight will be reduced to 1/8th that of the original, while the load-bearing capacity will only be reduced to 1/4th.

Hence, all these 10- foot "scale models" Truthers have produced over the years to attempt to "prove" the towers couldn't have collapsed, are actually capable of holding a much greater percentage of their own weight than the actual, real-life Twin Towers. Even when you build them out of materials much weaker than steel (such as cardboard), they still have a significant advantage, due to the much smaller scale.


Of course, if you're smart, your intuition should've already told you that Gage and Heiwa's little experiments weren't painting the right picture, but I thought you might like to know the science behind it.

And I am interested in seeing Heiwa's rebuttal.
 
Even with significant scale models(half scale for instance) it's still difficult to predict the scaling effect in a lot of situations.
NIST's testing of the 17', half scale, and 35',full scale, floor truss models showed significant differences between the predicted and observed fire rating.

A tiny desktop model isn't going to tell you anything interesting,at least not about the model.
 
Ryan Mackey discussed this in his Hardfire #3.

You must scale on the basis of mass and strength not size.

But detailed data on the tower is required to do that. So why has Mackey been complaining about me demanding to know the tons of steel and concrete on every level?

You people contradict yourselves.

psik
 
psikeyhackr said:
Ryan Mackey discussed this in his Hardfire #3.

You must scale on the basis of mass and strength not size.

But detailed data on the tower is required to do that. So why has Mackey been complaining about me demanding to know the tons of steel and concrete on every level?

You people contradict yourselves.

psik
Click to expand...

Everybody but you knows,or can work out, that data from the published specifications.I see you still haven't done it.
 
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psikeyhackr said:
But detailed data on the tower is required to do that. So why has Mackey been complaining about me demanding to know the tons of steel and concrete on every level?
Click to expand...

Because it's already known to a sufficient degree of accuracy. I suggest, once again, that you read one of the few papers in the Journal of 9/11 Studies that has any actual merit, in which Gregory Urich answers the exact question that you continue obsessively to ask.

Dave
 
psikeyhackr said:
Ryan Mackey discussed this in his Hardfire #3.

You must scale on the basis of mass and strength not size.

But detailed data on the tower is required to do that. So why has Mackey been complaining about me demanding to know the tons of steel and concrete on every level?

You people contradict yourselves.

psik
Click to expand...

you understand that this isnt a "scaling conspiracy theory" thread
so the actual mass isnt important for this discussion
i think even you can figure out that a 5 foot scale model will have different load bearing capacities than a full size skyscraper

just in case people still dont understand and need a simple and familiar example
an ant can carry 50 times its own weight - due to scaling
a 150lb ant wouldnt be able to do that (IIRC it would probably crush its legs and internal organs under its own weight)
 
1337m4n said:
You may have seen a number of Truthers try to make scale-models of the World Trade Center and use them to "prove" that the towers couldn't possibly have collapsed. Famous examples include Richard Gage with his cardboard boxes, and Heiwa with his pizza boxes and his (fake) $1 mil challenge.

<snip>

And I am interested in seeing Heiwa's rebuttal.
Click to expand...

Damn yooou!!!!!!!
You thought about the thread!!!!! Anyway I posted this before I put HI on ignore, maybe it'll have even more value to add here:

http://www.internationalskeptics.com/forums/showpost.php?p=3983414&postcount=76
Say for example we have an umbrella shaped shelter that is 10 ft & 10 ft deep with a flat concrete roof 1 ft thick and a single center column having an area of 1ft2.

Concrete is roughly 150 Lbs/ft3, the total load on the column is about 15 kips, and the compressive stress is 15 kips/ft2

Note: 1 kip = 1,000 lbs

Take the same structure and increase the size 3 fold, overall size increases to 30 ft in each dimension; The roof slab would increase in thickness to by 3 fold as well resulting in a slab with about 2700 ft3, and a weight of 405 kips. The area of the center column would increase to 9 ft2. The column stress would be 45 kips, which is three times that of the original smaller structure. In order to effect the same compressive stress , the column area would have to triple to 27 ft2 with column dimension increasing to 5.2 ft on each side.


In other words even using the same materials in you "analogy" would result in drastically different results. The problem is compounded just by using different materials... A 1 ft3 volume of concrete can be loaded with many times it's own weight, however a slab of concrete the size of a building may only support double it's own weight.
Click to expand...
 
1337m4n said:
You may have seen a number of Truthers try to make scale-models of the World Trade Center and use them to "prove" that the towers couldn't possibly have collapsed. Famous examples include Richard Gage with his cardboard boxes, and Heiwa with his pizza boxes and his (fake) $1 mil challenge.

These don't work. Read and learn this article about the Square-Cube Law.
Click to expand...

Well written. I'll add that I've yet to see a Twoofer model in which the the structure damaged to simulate the plane impact and weight weight is added in proportion to the 100+ tons of aircraft to simulate unplanned floor overloading, and the model is stuffed with something like cotton and lighter fluid and set it alight.
 
Scaling models is quite complicated. Obviously CT's like Gage try to make it too simplistic. Not only do you have to account for the scaling effects due to the difference in size, but it depends on what you are trying to learn from the model. They built scaled models of the towers and put them in wind tunnels during the design. Sometimes model ships are put in some liquid other than water. It's not as easy as pizza boxes and lemons, but it's not easy to convince people like Heiwa and Gage of that, apparently.
 
psikeyhackr said:
Ryan Mackey discussed this in his Hardfire #3.

You must scale on the basis of mass and strength not size.

But detailed data on the tower is required to do that. So why has Mackey been complaining about me demanding to know the tons of steel and concrete on every level?

You people contradict yourselves.

psik
Click to expand...

You mean like the way you did with your bamboo stick and toothpick model, or have we contradicted ourselves in some other way?
 
Reactor drone said:
Even with significant scale models(half scale for instance) it's still difficult to predict the scaling effect in a lot of situations.
NIST's testing of the 17', half scale, and 35',full scale, floor truss models showed significant differences between the predicted and observed fire rating.

A tiny desktop model isn't going to tell you anything interesting,at least not about the model.
Click to expand...

Indeed because the ability of an item to shed heat through radiation and convection is proportional to its surface area but it ability to store heat is proportional to its volume thus making scaling in thermal properties extremely difficult if you also wish to scale strength.

IIRC, A sphere has the smallest surface are to volume ratio of any geometric shape. That fact should also be considered, the specific shape of an object matters.
 
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Dave Rogers said:
Because it's already known to a sufficient degree of accuracy. I suggest, once again, that you read one of the few papers in the Journal of 9/11 Studies that has any actual merit, in which Gregory Urich answers the exact question that you continue obsessively to ask.

Dave
Click to expand...
.
Gregory Urich does an interpolation on the exterior wall panels and he admits that. I have his spreadsheet. Why should anyone be interpolating something that the NIST should know and release and had 3 years to do?

psik
 
Sword_Of_Truth said:
You mean like the way you did with your bamboo stick and toothpick model, or have we contradicted ourselves in some other way?
Click to expand...
.
You are free to explain my supposed contradiction.

I compared the behavior of toothpicks without the mass of washers to toohpicks with the mass of washers. It should not be an intellectual challenge for normal people to extrapolate the significance of mass in the collaspe of the WTC.

Of course it could be a challenge for SOME people.

psik
 
psi

you seem to be missing the point.
your washers and toothpick attempt at scaling wasn't anywhere near accurate because toothipicks and washers are NOT scaled to anywhere near the rated strength of the stee as it would be scaled down.

It is one of the things that Ryan Mackey pointed out in his Physics of 9/11 part 3 interview on hardfire.

so while it is nice that toothpicks can be broken easily, that doesn't mean they have ANYWHERE near the same abilities as scaled down steel beams to the mass of the washers. (which is the POINT OF THE OP, which you seem to have missed)
 
psikeyhackr said:
.
You are free to explain my supposed contradiction.

I compared the behavior of toothpicks without the mass of washers to toohpicks with the mass of washers. It should not be an intellectual challenge for normal people to extrapolate the significance of mass in the collaspe of the WTC.

Of course it could be a challenge for SOME people.

psik
Click to expand...

my model looks nicer :p
weights1.jpg
 
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