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Bob, they 'ironed' lead? Did that make it stronger?  Wow, sometimes your puns are panefully transparent... And yes, definitely good to see you again, Ladymoon! I'm sure your former boss was right about customers buying more when they see glass blown. It looks magical. Dick Francis' last book had a glassblower as the main character. This book, like all of his, has some informational material on whatever the character's trade is.
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Joined: Nov 2000
Posts: 3,439
Carpal Tunnel
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Carpal Tunnel
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Check your Email, Jackie!
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Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
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Carpal Tunnel
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Many years ago there was a glass factory in Sandwich, MA, near east end of Cape Cod Canal. They made very attractive cut glass formal table ware. My mother had a very fragile glass cabinet of pitchers and goblets. Many scoldings I got for running through the dining room, because the vibrations might damage one of the goblets. They were just for looks. I don't remember their ever being used.
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Joined: Sep 2000
Posts: 2,891
Carpal Tunnel
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My son does not believe me about this whole glass being a super cooled liquid thing. Does anybody have a web site they can refer me to so that I can say "et vlan."
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Joined: Oct 2000
Posts: 5,400
Carpal Tunnel
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a more common liquid, that has some of glasses properties, is silly putty!
it is more liquid, but if you give it a sharp snap, it pops, and breaks "clean". think about? does liquid water ever snap and break clean? no! there are lots of others liquids that behave "unliquid-y"!
trouble is, your son thinks all liquids follow the "general rules" for liquids..(ie the rules first noted by Newton, i.e., liquids flow, (they don't hold there shape) they take the shape of what ever contains them, there viscosity is effected by tempature (actually this is true of glass at high heat, but not at "room temperature", and so on.)
for example... think what would happen if you put an electric mixer (turned on!)into a full bowl of water-- a shower! (a common liquid, acting as we (and Newton!) expect.
but take an other liquid (here you have a choice-- egg whites, or STP motor oil treatment!) turn the mixer on, put them in the bowl.. and no shower.. in fact, rather than being flung away (as water and most liquids would be) egg white and STP cling to the beaters! (that why STP works in your engine, the actions of the engine actualy attract the STP, and increase the lubrication effect!)
Glass is not a common liquid, and it doesn't obey the general rules. but "non-newtonian" fluids are fairly common.. send me a PM for more interesting "kitchen science" experiments!
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Dear belMarduk: I searched Yahoo for "Physics glass supercooled solution" and got this URL. It is very hard reading, but at least your son can gather that the idea is scientifically accepted.: http://www.ttu.edu/~chem/faculty/quitevis/quitevis.html
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Joined: Jan 2001
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Carpal Tunnel
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Dear belMarduk: if your son likes to do simple experiments, here is one about glass he might enjoy. Prince Rupert (let your son look him up) was a scientific dilettante, and is credited with discovering that if a glass rod is melted in a burner flame, and allowed to cause drops of molten glass to fall into the water, the resulting "tadpoles" have the peculiar property of breaking into tiny pieces if the tail is broken. http://www.thecure.com/robertpages/princerupertsdrops.html
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Joined: Oct 2000
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Yeah, the cause is similar to "silly putty" it has to do with how the molocules are aligned, especially under stress.
Under stress, silly putty's molocules align at right angles to the stress, so a sharp pull, results in a clean, almost sliced surface.. (where as gentle pressure cause it to stretch.)
dropping hot liquid glass into water, causes a sharp cooling effect, which lines up stress in the glass..
depending on your utility service you might be able to do it over a kitchen stove..
Starting in the 1950's Con Ed added water vapor to the natural gas, so you get few BTU out of a given volume. (you used be be able to melt lead, for plumbing work over the stove!) now you need to use a butane torch.
an other cool liquid, is a suspention of corn starch.. add enough corn starch to about two cups of water (about 1 cup) to make a fluid about as thick as cream.
pour into a pie pan, or some other flat shallow dish.
Rapidly, and hard, smack the fluid! No, no splashes! it too, aligns its self under stress. and a hard smack causes the liquid to behave like a solid! leave your hand there for a moment or two, and you can feel it return to liquid state, and you hand will gentle sink in!
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Joined: Jan 2001
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Quite a while ago, there was a thread that mentioned thixotropism. When penicillin was first used, it was in a watery solution. But then a creamy liquid concentrate was developed that looked as though it would not go through a fine needle. But it had the property of becoming much less viscous when drawn into a needle. This is called thixotropism. I don't know how it was achieved.
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Why wasn't Science classes this much fun and interesting?
Great thread.
Thank you all.
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