What is the most viscous fluid in your everyday use around your home?

at ambient temperature.

I'm in for Lyle's Golden Syrup and I'll raise you to:

It doesn't count: it's a rheopectic pseudoplastic.

I'll double your syrup and raise you to treacle.

I'm in for treacle and I'll raise you to:

Glass.

Glass ? Glass is not a fluid.

Are you sure about that?.....

I vaugely remember reading somewhere that a vertical sheet of glass will eventually become thicker at the bottom than the top as the glass flows, very, very, very, very slowly.

Can either of us be bothered to check it out?

I can vouch for that by direct experience. The panes in the upper windows in an 1839 house we lived in were thicker at the bottom.

Thats old tale in the inspection old glass they found it thicker at the bottom then at the top. In the research that followed they found the the old flat glass was rolled out like dough or spun like a pizza. The outer edges were thicker. When installing the glass they found it set better with the thick edge down.

Never Mind Answered below.

Been there... Done That... Had a 100 year old house once. Glass is my guess too Dell... You beat me to it.

Sincerely

Bill

this says it is a missconception. no prize for me today!

Glass as a liquid

This section needs additional references or sources to facilitate its verification.
Please help improve this article by adding reliable references
Unverifiable material may be challenged and removed.
This article has been tagged since August 2007.

Glass is generally treated as an amorphous solid rather than a liquid, though different views can be justified since characterizing glass as either 'solid' or 'liquid' is not an entirely straightforward matter.^[5] However, the notion that glass flows to an appreciable extent over extended periods of time is not supported by empirical research or theoretical analysis.

A myth does exist that glass rods and tubes can bend under their own weight over time. To test this, in the 1920s, Robert John Rayleigh, son of the Nobel Prize winner John William Rayleigh, conducted an experiment on a 1 metre (~39 in) long, 5 millimetre (~3/16 in) thick glass rod, which was supported horizontally on two pins with a 300 gram (~0.66 lb) weight in the middle. Apart from the initial bending of 28 millimetre (~1.1 in), the position of the weight did not change until the end of the experiment, which lasted for 7 years.^{[citation needed]} At the same time, another man, a worker of General Electric named K. D. Spenser, conducted a similar experiment independently. Two months after Rayleigh, he published his own results which also disproved the myth.^{[citation needed]} Spenser suggested that the myth was composed before the 1920s, when the tubes were made by hand, and naturally some of them were curved to begin with. Over time the straight tubes were taken away, and only the curved ones remained. Some people probably thought it was the glass flowing.

Some people believe glass is a liquid due to its lack of a first-order phase transition. There is no discontinuous change of density and no latent heat of fusion. However, glass does go through a second-order phase transition where the thermal expansivity and heat capacity change markedly.^[5][6]

Although glass has properties of a supercooled liquid, it is generally classed as solid at room temperature.^[7] There is also the problem that a supercooled liquid is still a liquid — moves and behaves like a liquid, not a solid — but is below the freezing point of the material and will crystalize almost instantly if a crystal is added as a core.

[edit] Behavior of antique glass

The observation that old windows are often thicker at the bottom than at the top is often offered as supporting evidence for the view that glass flows over a matter of centuries. It is then assumed that the glass was once uniform, but has flowed to its new shape, which is a property of liquid. The likely source of this belief is that when panes of glass were commonly made by glassblowers, the technique used was to spin molten glass so as to create a round, mostly flat and even plate (the Crown glass process, described above). This plate was then cut to fit a window. The pieces were not, however, absolutely flat; the edges of the disk would be thicker because of centrifugal forces. When actually installed in a window frame, the glass would be placed thicker side down for the sake of stability and visual sparkle. Occasionally such glass has been found thinner side down, as would be caused by carelessness at the time of installation.^{[citation needed]}

Mass production of glass window panes in the early twentieth century caused a similar effect. In glass factories, molten glass was poured onto a large cooling table and allowed to spread. The resulting glass is thicker at the location of the pour, located at the center of the large sheet.^{[citation needed]} These sheets were cut into smaller window panes with nonuniform thickness. Modern glass intended for windows is produced as float glass and is very uniform in thickness.

Several other points indicate that the 'cathedral glass' theory is misconceived:

• Writing in the American Journal of Physics,^[8] physicist Edgar D. Zanotto states "...the predicted relaxation time for GeO₂ at room temperature is 10³² years. Hence, the relaxation period (characteristic flow time) of cathedral glasses would be even longer" (Am. J. Phys, 66(5):392–5, May 1998). In layman's terms, he wrote that glass at room temperature is very strongly on the solid side of the spectrum from solids to liquids.
• If medieval glass has flowed perceptibly, then ancient Roman and Egyptian objects should have flowed proportionately more—but this is not observed. Similarly, prehistoric obsidian blades should have lost their edge; this is not observed either.^{[citation needed]}
• If glass flows at a rate that allows changes to be seen with the naked eye after centuries, then changes in optical telescope mirrors should be observable (by interferometry) in a matter of days—but this also is not observed. Similarly, it should not be possible to see Newton's rings between decade-old fragments of window glass—but this can in fact be quite easily done.^{[citation needed]}
• Glass in refracting telescopes, with objective lenses of large diameter, are observed to sag under their own weight (causing a loss of focus), but this is due to elastic deformation and not because of the glass flowing over time; this (along with chromatic aberration and other effects) limits the size of refracting telescopes, with the largest refractor in the world being the Yerkes Observatory telescope with a diameter of 102 centimetres (40 in).
• The "cathedral glass" phenomenon that is often cited as a demonstration of flow generally refers to old leaded glass windows in churches. The windows often appear to have sagged at their bottoms. On closer examination, it is found that the individual pieces of glass have remained flat, and that the bending has occurred at the soft lead "cames" that join the pieces. This bending may be largely due to successive thermal expansions and contractions of the glass over time, combined with the constant weight of the glass above. The lead cames are essentially plastic; that is, they tend not to recover their original shape after being distorted. Thus, successive temperature fluctuations are able to create progressive deformations, and the illusion of flow.^{[citation needed]}

Ouch! That second bullet point really hit the point!!!

Consider that the glass bending experiments were at ambient temperature. Now, consider running the same experiments at progressively higher temperatures and determine at what temperature the glass begins to flow. I do believe that glass blowers take advantage of this flow characteristic. As for a uniform thickness for glass, it can be achieved by placing the glass on molten steel or other metal and allowing it to flow to a uniform thickness then cooled to lock it in.

One can also consider ice to be a fluid, too. It does flow but it also has a crystalline structure. The argument here can be made that the point of fluidity, however, is at a point of melt and refreezing. Now, tell all that to the glaciers.

Oh crap, Ozzb.

Now you've gone and done it for sure! Why man? for the love of God why?

cr3

Without consulting any reference materials, I would reply: "indeed it is", in agreement with Monsieur Del.

With reference materials:

http://en.wikipedia.org/wiki/Glass - superb article with plenty of references. Well it appears it's quite a debate even among those who Really Know. So I guess I change my opinion (which till now had been that it's a super-cooled liquid), it's enough of a solid for me to exclude it from being an eligible answer to this question. And because this has the sound of a 'simple/trick-question', I suspect we'll have a LONG debate about this one!

;--)

Nice weekend all

RFg

What a smashing suggestion, though!

I think Kris is away on holiday...I'm sure we could pencil him in for some custard!

(That would be hot of course)

http://wikipedia.org/wiki/Frozen-custard

Or maybe served at room temperature with yorkshire Pud

This thread is making me feel very hungry!

And I will 'raise' to this!!!

Oooooh, a FemTote.

Cheers for nominating Custard Del . My alter ego says it may depend what your house is made of, and where it is. It could of course just be semantic silliness, with crystals sliding over each other, but salt pillars bulging slowly over years looks nice. I reckon somebody kept turning that Egyptian stuff and Maya knives over and over, or maybe they just didn't stack 'em high enough. My post here is a bit hurried, I'm just creeping around too fast. It's time to ooze off my chair....Hang on a mo, can something be viscous if it isn't a fluid ? I'm claiming foul for question-ambiguity - it should have read "viscous substance".

I have kids, so silly putty is the most viscous common fluid around my house.

How about:

• Peanut butter (creamy of course); or
• Crisco shortening

I believe that both are classed as fluids...

For the peanut butter, go with the organic stuff they grind at health food stores - about a gazillion centipoises.

Just make sure that the health food store you buy it from cleans out the grinding machine regularly... The mold that forms on peanuts & residue in these grinders can produce toxic metabolites referred to as aflatoxins. Some aflatoxins are potent carcinogens...

The most potent known! That's why every year the US gov. Takes statistics on peanut butter in reference to the cancer rate.

Put both on two pieces of bread and you have a party or a heart attack... Your choice.

Mayonaise

Good old Vegemite or maybe Honey

Or it could be

From our house:

(My wife says I'm thick, dense and sloooow . . . . at 23*C)

It is the mastic tar seal on your roof, or the asphalt in the drive way. Also, the caulking around the tub, shower, or windows.

ketsup

Yes, but that a sheer-thinning fluid.

Nooooooooooo! It's a rheopectic pseudoplastic (surely this phrase will catch on soon?)!

Petroleum jelly.

It's great on a cracker.

cr3

Petroleum jelly. It's great on a cracker.

------

Y2K Jelly, on toast.

Glass.

I bet for a biological substance: what about "#2" ?

(in some neighbourhoods also referred to as SH*T)

How about bitumen? Jeff

Heinz Catsup

I'd guess glass. Don't know if anyybody else says that, haven't read posts yet, I'll do that now.

Cheers......Codey

How about ?

As far as I can remember, some glasses, even though they are amorphous, can have a long range ordering, which would mean they'd stop being a liquid...

On the other hand, I'd vote for the amorphous LDPE tray for making ice-cubes in your freezer. It's amorphous and still somehow more viscous than peanut butter

"what is the most viscous fluid"

A mixed epoxy glue component that is about to dry could be very viscous indeed!

Like this one?

We prefer KY Jelly.

I'm going with the malt extract I keep in my fridge....

I bent a spoon trying to get some out of the jar, until I warmed it up...

John.

This chap keeps it in a large drum, and a bit warmer, by the look of it. Great for making Porter! No bent spoons here. Eat yer heart out, Yuri Geller!

CREST COLGATE or AIM whatever is on sale

Amazing but not surprising, 98 % of the viscous fluids mentioned are edibles.

What about grease?

You haven't tasted my ex's cooking. Believe me, grease is edible. If you work at it. Personally, I think her cooking should be listed under "WMD."

Not so much 'Cordon Bleu', more 'cordoned off', perhaps?

It's edible too.

cr3

Printer ink is more viscous then lard, both of which fall behind molasses. Its interesting to note that depending on where you look, glass IS sometimes listed as a viscous complex liquid, along with most common items. Its viscosity at room temperature is is high as 10^21 η (Pa·s), with tar coming in at about 30k.

Of course, the most thick, slow moving thing in my home would be the lady of the house. Sigh...

Logged as 'Guest' indeed.

Does she have access to your email, 'cause I'm tellin'!!!

my answer is "glass". However, today, some plastics might qualify as a fluid, too.

I believe the most viscous fluid is window glass. Although it appears solid, it is actually flowing very slowly downward. Old window glass (1000 years old maybe) can be measure to confirm that it is actually thicker at the bottom.

My answer to the class was "Glass" which sparked quite a discussion by young graduate students and 3 PhDs in the room. The web has many articles on this.

PetroPower,

Both of the links are to pages that appear to conclude that, for all intents and purposes, glass IS NOT a viscous fluid...

Furthermore, based upon the excerpt of the ASTM test method that appears in one of the links, several of the "fluids" identified by various posters, would actually be classed as solids by ASTM...

BTW, just what kind of a pump would you design in your "pump class" that could handle glass as a viscous fluid???

Hi JMAN

The question in class was not about pumping glass; my ex-wife is as expert at that as I am at dodging it!

As I spoke about viscosity and the effects on pumping, and used a project as an example that was 1000 cSt, one young lady couldn't get a grasp on how viscous that was so she asked about common household 'things' that were 1000 cSt. This prompted another student (masters degree in fluid mechanics), quite possibly setting me up to answer incorrectly (which seems I did) to ask what is the most viscous stuff laying about our common world. I said glass (which was his opinion also . . . so I took a ham bone of his plate if he was setting me up), however, my answer sparked as much class room debate as shown herein. These departures from topic in classes help get the blood pressure up inside sleepy students ! I lost my ego 20 years ago and it's fun to use young egos to stir the pot a bit, when, the answer has NOTHING to do with the class. But it does keep neurons jumping about in the brain which is good; kind-of a neural network pigging, to use a pipeline term. (Oh darn it . . . I hope I didn't just open up a new topic on neurons . . . . or pigging for that matter).

Glass seems to be a solquid !

So, PetroPower, you duck and cover, hehehehe. Now try your students with my question in the 'general forum' if you dare; it has to do with detecting and measuring objects (or energy) that is faster than the speed of light. I think this is attracting some attention, too.

Yours, a former Principle Mechanical Designer from the petrochemical industry.

<pumping glass>

Lots of people pump iron.

You haven't seen the custard that I can make.

I obtained the recipe from an old Navy Chief cook.

My porridge isn't bad either, I use the same recipe, the only problem that I have, is if the porridge goes cold, I have to throw the bowl out with it.

Hey My mother used to make porridge like that You could make really good castles with moats around them and they would stay there. After you sprinkled on brown sugar and cream (real cream straight from the house cow and still warm) it took ten minutes to mix it together so you could eat it with a spoon.

I think that is a universal experience. Why do parents expect their kids to eat this stuff or even need it for that matter?!

What's the matter with porridge vermin? It's good tucker, makes your hair curly.

I am 67 and still have my hair, except for the hole in the middle. I think that this is caused by head growing through my hair!!!

Watch out, MOBI, I at 67 I had my hair, teeth, sight, hearing, and mind; now that I am 74 I am losing them all.

Hi chtant, did you eat your porridge when you were a kid?

Yes, MOBI, I did. Also Hominy grits, scraple, yard chicken, polk, and many other poor people food. I was born in 1933 in Oklahoma and my parents were victims of the great depression as were many other Oklahomas of pioneering stock.

It appears as though you did well.

The great depression must have been bad for many people earth wide and I reckon under those conditions one would have been glad of porridge.

We cleaned our plates, washing afterward not required. To this day, the clean plate remains with me, I guess I am now too lazy or feeble to wash dishes, hehehehe. Actually, I am very good about rinsing and putting my eating utensils in the dishwasher.

I had my mind until I turned 40. Now I don't care about the others. What were we talking about?

Men who are balding at the forehead are thinkers.

Men who are balding at the top are lovers.

Men who are balding at both only think they're lovers.

I always thought there must be something good about going bald on top.

How true that is!!

The mind is certainly willing!!!!

It's a matter of mind over matter. If you don't mind, it doesn't matter.

The most viscous fluid we vermin know about is that nasty stuff they put in Roach Motels!

Too true. That reminds me of the saying:-

"Once a king, always a king

Once a knight is enough"

Glass

I was going to say a chocolate bar but I like all the rest of these answers better.

My girl friend once asked if her butt looked big in these pants.........I said no just thick. I don't know how that can be measured........

Use a cheek-o-meter, similar to Rockwell harness tester but it's used to measure density versus volume and has an algorithm to compute viscosity and it is actually a sonic 'sound' device. How it works, (and everyone has one of these cheek-o-meters) >>> You kneel down behind her and shout "Hey jiggly butt . . . why do you shake like a hound dog trying to pass a peach pit ?" and you will get a reply . . . . I think it will be in metric units.

But call 911 and make a reservation just in case the viscosity reading comes out too low.

Without doubt, the thickest things in Nouvions are those stupid British aviators.