The author, Ted Heindel, a mechanical engineer who studies fluid flows, explains why it made sense for the TSA to subject a jar of Jif to the 3.4-ounce rule about "liquids." It may seem wrong, but how much do you really know about what is a liquid?
Any material that flows continuously when a shearing force is applied is a fluid. Think of a shearing force as a cutting action through a substance that causes it to flow continuously. For example, moving your arm causes the surrounding air to change shape—or deform, to use the physics term—and flow out of the way. The same thing happens to water when your arm takes a swim stroke. There are many kinds of fluids....
Air and water are Newtonian fluids — "the shear force varies in direct proportion with the stress it puts on the material." Peanut butter is a non-Newtonian fluid:
If you stir really fast, with more shearing force, the PB gets runnier; if you stir slowly, the PB remains stiff.... It doesn’t flow as easily as air or water, but it will flow if sufficient force is applied.... How easily it flows will also depend on temperature—you may have experienced peanut-butter drips on warm toast.....
But when is a fluid a liquid?
Both gases and liquids can be deformed and poured into containers, and will take the shape of their container. But gases can be compressed, whereas liquids cannot—at least, not easily. Peanut butter can be poured into a container, at which point it deforms, or takes the shape of that container.....
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31 comments:
Meanwhile, millions of illegals are invading our borders, with diseases, drugs and GOD knows what else, and they don't give a shit.
Imagine pulling out your jar of peanut butter on the plane and hearing the shrieks of terror from parents whose kids have a peanut allergy. You may get placed on the no fly list.
Gasses are fluids at large scale, meaning having only a single velocity at a single point. At small scales, there's only a relation of velocity average and position. Then they obey a Boltzman law (many velocities at a given position) instead of the Navier Stokes equations (single velocity at a single position).
The way that large scale energy of motion cascades down to smaller and smaller scales and eventually winds up as heat is that it reaches the Boltzman scale and is just kicking individual molecules with more energy instead of moving the fluid.
A nice succinct description from Wikipedia.
Liquids have a "definite volume but no fixed shape".
When is a boy a girl? When is a girl a boy?
The first time I saw a peanut grinder in a hippie grocery store and watched the butter flow out of it I thought, "Peanut butter looks like diarrhea." Luckily it solidifies later and looks more edible. Sort of.
If I put you in a giant blender then eventually you'd be a liquid too...
as if the argument / rule is about 3-4 oz or liquids when it is about should there be TSA at all!
and then there is liquid v fluid
True story: A few years ago my wife and I were on a long flight and had put some "trail mix" in the camera bag to munch on, since they were only going to serve us little packages of pretzels. The trail mix had seeds, nuts, dried fruits, and chocolate. And yes, some of the nuts were peanuts. At some point we opened the bag and ate some of the trail mix with coffee, and a flight attendant got on the intercom and told the whole plane that this was a "no peanut" flight, and one of the passengers had a peanut allergy, and so would the offending passengers please put the peanuts away.
Steel is a liquid at high temperatures. Diamonds can be pulverized and made to flow. Soylent Green (e.g. planned populationhood)... Everything is ultimately a liquid when subject to sufficient mechanical or thermal force.
A fluid is a material that has no shear strength.
Glass is a liquid on a long enough time scale. See very old windowns.
"It may seem wrong, but how much do you really know about what is a liquid?"
The justification for the TSA rule is to prevent people from bringing on binary liquid explosives, which is to say two liquids that can be combined together to make an explosive, though neither one is itself explosive, and so neither one will show up on a chemical "explosive sniffer"
So unless you can demonstrate a binary explosive with one part being peanut butter, there is not the slightest justification for the TSA banning it
They need more precision using this "How easily it flows will also depend on temperature" then steel, aluminum, etc. are fluids...if you get them hot enough. They flow, can be poured and take the shape of their container. So they need to specify that we are talking about liquids at normal room temperature of around 25 C.
Sure it's a liquid. Go ahead. Drink it. Like you drink other spreads and butters.
Thirsty, Mr TSA man? Let me offer you some quenching cream cheese or hummus.
Or he could have avoided the whole situation by simply making his PB&J sandwich ahead of time, wrapping it up, putting it in his carry-on bag, and then leaving the jar back at home. Kinda like my mom used to do when she filled up my first grade lunchbox before I left for school in 1958.
IMHO, sometimes it's just easier on everyone involved to do some simple food prep rather than getting into an argument about fluid dynamics with TSA agents.
I disagree. Cats are more liquid than peanut butter.
See r/catsareliquid
The solution (!) is obvious: take the chunky, leave the creamy.
Glass can be considered a fluid.
My husband's spreadable cheese was confiscated as a "liquid." He thought the TSA agents were hungry.
So unless you can demonstrate a binary explosive with one part being peanut butter, there is not the slightest justification for the TSA banning it
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is that like proving a negative?
call Trump to witness expertise!
will TSA grab him by pussy?
Given the underlying rule makes no sense, it cannot actually make sense for the TSA to apply it to anything.
There has not been a bombing on a domestic flight since the TSA was created. That means that the TSA has caught all the bombers before they could set off their bombs!
Of course, the TSA has never caught a bomber. Ever. Not one.
kids have a peanut allergy
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so no 'gain of function by humans' for humans research by Fauci on mitigating for kids have a peanut allergy
[NIAID conducts and supports basic and applied research to better understand, treat, and ultimately prevent infectious, immunologic, and allergic diseases. ]
This is exactly the type of result you should expect from a government bureaucracy that sees fit to draw distinctions based upon an object's thermodynamic phase. As if colloids are safe.....Seize all the things!
So unless you can demonstrate a binary explosive with one part being peanut butter, there is not the slightest justification for the TSA banning it
Innocent until proven guilty is a critical principle of our conservative national judicial temperament and a civil right of citizens, and of legal immigrants and visitors by statute.
Why is 3.4 oz of it acceptable and 8 oz is not? The whole thing is just arbitrary gov't bullshit.
The point of the rule is to look for explosives. You don't think you could put explosive in a peanut butter jar?
Narayanan said...
So unless you can demonstrate a binary explosive with one part being peanut butter, there is not the slightest justification for the TSA banning it
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is that like proving a negative?
No, that's "proving a positive"
If they can make something blow up with peanut butter, they can ban peanut butter
if they can't, then they can't ban it
NotWhoIUsedtoBe said...
The point of the rule is to look for explosives. You don't think you could put explosive in a peanut butter jar?
They can swipe and test for explosives. So no, there's no legitimate grounds for them to force you to throw away the jar, if you're willing to go through the swipe test
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