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06/02/2003 03:58:14 AM · #1 |
1. butter
2. toothpaste
3. jello
4. mercury (i learn in science it's solid)
darn, another 2 more day to go. I'm still having a mental-block on what to shoot. come on.... |
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06/02/2003 04:13:52 AM · #2 |
The first three do not readily flow, so the are solids. Mercury has the characteristics of a liquid so I would say it is, even though it may not be technically, and I'm sure people here will see it as a liquid.
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06/02/2003 04:37:37 AM · #3 |
Shadow, all of the substances you mentioned, except mercury, are solids at room temperature. The best way to define the term liquid, is to describe it as a transitionary state between solid and gas phases. Some common properties of liquids are:
- They are not compressible. All gasses can be compressed, since there is a lot of open space between individual gas molecules. With liquids this is not the case.
- They will readily take the shape of any container. In other words, because the forces between different molecules are relatively weak, liquids will adapt to the shape of the container they are in. (they flow)
- Thirdly, and probably most importantly, since liquids are transitionary states of materials, all liquids have boiling points where they turn into gasses, and freezing points where they turn into solids.
Mercury is a liquid at room temperature. It freezes at -38,87 degrees Celcius, and it boils at approximately 357 degrees Celcius.
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06/02/2003 04:40:16 AM · #4 |
Originally posted by greenem2:
...I'm sure people here will see it as a liquid. |
That's the problem here, isn't it? It's always how people see it. I can say "telephone" and there goes people thinking about Alexander Graham Bell, or their modems connected to a telephone line, or maybe a flower growing beside a telephone pole. hehe... neat. I guess the "topic of the week" is only followed by "uncreative" people |
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06/02/2003 04:49:45 AM · #5 |
Jello at room temperature will liquify.
Toothpate and butter are complex structures with both solid and liquid components, but at "room texture" they both act like extremely viscous liquids -- think of trying to squeeze out a vertical column or large mound of toothpaste and imagining what it would do, or of some butter sitting on the table and taking on the shape of the dish it's in...
Glass, by the way, is a supercooled liquid with a non-crystalline structure, and flows slowly at ordinary temperatures (real old windows become thicker at the bottom). |
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06/02/2003 05:27:16 AM · #6 |
Originally posted by GeneralE:
Glass, by the way, is a supercooled liquid with a non-crystalline structure, and flows slowly at ordinary temperatures (real old windows become thicker at the bottom). |
This is not true, despite the widespread and apparently unshakeable belief in it.
//www.glassnotes.com/WindowPanes.html
//www.ualberta.ca/~bderksen/florin.html
//www.robinsonglass.com/analysis.htm
//www.urbanlegends.com/science/glass.flow/origins_of_claim.html
Just doing my best to kill urban legends. |
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06/02/2003 05:38:10 AM · #7 |
Originally posted by GeneralE:
Jello at room temperature will liquify.
Toothpate and butter are complex structures with both solid and liquid components, but at "room texture" they both act like extremely viscous liquids -- think of trying to squeeze out a vertical column or large mound of toothpaste and imagining what it would do, or of some butter sitting on the table and taking on the shape of the dish it's in...
Glass, by the way, is a supercooled liquid with a non-crystalline structure, and flows slowly at ordinary temperatures (real old windows become thicker at the bottom). |
Agreed, Since jello will liquify at room temperature (ie melt), jello must be a solid.
Though toothpaste and butter are both complex gels, which do act like extremely viscous liquids at room temperature, I do not believe they can be classified as liquids, in fact they are more commonly refered to as semi-solids. Gels are colloidal mixtures of liquids and solids in which the solids have linked together to form a continuous network, becoming very viscous (resistant to flow).
Although it would be almost impossible to squeeze out a vertical column of toothpaste (which will not deform quickly), it would be equally frustrating to wait for toothpaste to take on the shape of the container you squeeze it into. There are many examples of solids which would, under the right conditions, applying enough force act as liquids, but this does not mean that they are in fact liquids.
Although, according to popular science, glass is considered to be a liquid at room temperature, this is infact not true. It is sometimes said that glass in very old churches is thicker at the bottom than at the top because glass is a liquid, and so over several centuries it has flowed towards the bottom. This is not true. In Mediaeval times panes of glass were often made by the Crown glass process. A lump of molten glass was rolled, blown, expanded, flattened and finally spun into a disc before being cut into panes. The sheets were thicker towards the edge of the disc and were usually installed with the heavier side at the bottom. Other techniques of forming glass panes have been used but it is only the relatively recent float glass processes which have produced good quality flat sheets of glass.
To answer the question "Is glass liquid or solid?" we have to understand its thermodynamic and material properties.
Some people claim that glass is actually a supercooled liquid because there is no first order phase transition as it cools. In fact, there is a second order transition between the supercooled liquid state and the glass state, so a distinction can still be drawn. The transition is not as dramatic as the phase change that takes you from liquid to crystalline solids. There is no discontinuous change of density and no latent heat of fusion. The transition can be detected as a marked change in the thermal expansivity and heat capacity of the material.
The temperature at which the glass transition takes place can vary according to how slowly the material cools. If it cools slowly it has longer to relax, the transition occurs at a lower temperature and the glass formed is more dense. If it cools very slowly it will crystallise, so there is a minimum limit to the glass transition temperature.
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06/02/2003 12:37:22 PM · #8 |
Originally posted by shadow:
1. butter
2. toothpaste
3. jello
4. mercury (i learn in science it's solid)
darn, another 2 more day to go. I'm still having a mental-block on what to shoot. come on.... |
My opinions: If you melted the butter, sure. If you didn't let the jello cool and harden, sure. Mercury, sure. Toothpaste would be a real stretch.
My idea has yet to be mentioned on the forums (hallelujah) but I still have a feeling there will be about 10 people interpreting the challenge in the same way as me. Sigh. Oh well! :) Just go have fun with it, and don't stress out, okay? |
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06/02/2003 12:41:02 PM · #9 |
Originally posted by shadow:
1. butter
2. toothpaste
3. jello
4. mercury (i learn in science it's solid)
darn, another 2 more day to go. I'm still having a mental-block on what to shoot. come on.... |
Any matter that can be squeezed out at room temp (20C) is liquid! |
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06/02/2003 12:58:17 PM · #10 |
Good set of links. I actually was thinking more of large plate-glass windows, not stained glass. However, the gist of all of these still seems to be that glass is a liquid whose vicosity has increased to the point where the flow rate at ordinary temperatures is immeasurable in typically relevant periods (like days or years or centuries).
And this result from the "standard test" suggests these experimenters allow for some pretty runny "solids"
9. Interpretation of results.
9.1. A material that flows a total of 2 in (50 mm) or less within 3 min is considered a solid. Otherwise it is considered a liquid.
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06/02/2003 01:14:16 PM · #11 |
Originally posted by GeneralE
Just doing my best to kill urban legends.[/quote:
Good set of links. I actually was thinking more of large plate-glass windows, not stained glass. However, the gist of all of these still seems to be that glass is a liquid whose vicosity has increased to the point where the flow rate at ordinary temperatures is immeasurable in typically relevant periods (like days or years or centuries).
And this result from the "standard test" suggests these experimenters allow for some pretty runny "solids"
9. Interpretation of results.
9.1. A material that flows a total of 2 in (50 mm) or less within 3 min is considered a solid. Otherwise it is considered a liquid.
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If you read my post above, you will see that with all glass, no matter how slowly it is cooled to prevent crystalisation, there is a very definite point where phase transition from liquid to solid occurs. This can be recognised by a marked change in the thermal expansivity and thermal conductivity of the material, a change typical of phase transition with all materials.
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06/02/2003 01:22:38 PM · #12 |
Originally posted by carolee:
Originally posted by shadow:
1. butter
2. toothpaste
3. jello
4. mercury (i learn in science it's solid)
darn, another 2 more day to go. I'm still having a mental-block on what to shoot. come on.... |
My opinions: If you melted the butter, sure. If you didn't let the jello cool and harden, sure. Mercury, sure. Toothpaste would be a real stretch.
My idea has yet to be mentioned on the forums (hallelujah) but I still have a feeling there will be about 10 people interpreting the challenge in the same way as me. Sigh. Oh well! :) Just go have fun with it, and don't stress out, okay? |
Actually ... now if you go to the grocery stores and get toothpaste .. you can get it in a LIQUID GEL (says it right on the bottle)... that stuff rocks! :)
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06/02/2003 01:55:29 PM · #13 |
Originally posted by Martus:
If you read my post above, you will see that with all glass, no matter how slowly it is cooled to prevent crystalisation, there is a very definite point where phase transition from liquid to solid occurs. This can be recognised by a marked change in the thermal expansivity and thermal conductivity of the material, a change typical of phase transition with all materials. |
I suppose ... been too long since I was in science class, where I actually got to blow some glass (not very well). And I know someone who was at the big art glass school near Seattle. I'm not planning to use it myself though, although I have a gas/oxygen burner in a box somewhere I could use to melt some glass.... |
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06/02/2003 02:13:00 PM · #14 |
Originally posted by GeneralE:
I suppose ... been too long since I was in science class, where I actually got to blow some glass (not very well). And I know someone who was at the big art glass school near Seattle. I'm not planning to use it myself though, although I have a gas/oxygen burner in a box somewhere I could use to melt some glass.... |
I've always wanted to try glass blowing, but I'm too unhandy, I'd probably end up burning the house down or something :)
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06/02/2003 10:49:53 PM · #15 |
| I thought you needed super hot kilns for that sort of thing... not exactly what you'd find in the kitchen. |
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06/02/2003 10:53:38 PM · #16 |
Isn't human body a liquid?
What percentage of the human body is water?
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06/02/2003 11:07:27 PM · #17 |
Originally posted by indigo997:
I thought you needed super hot kilns for that sort of thing... not exactly what you'd find in the kitchen. |
Soft laboratory glass (like is used to make a small-animal drinking tube) will probably soften sufficiently over a good-quality gas kitchen stove. And the burner I have in a box somewhere uses both gas and oxygen, and can melt Pyrex(R) glass.
I'm talking about bending and forming smaller pieces to start with, not the kind of glassblowing where you pick up a glob of molten glass on the end of a metal pipe and blow that. |
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06/03/2003 11:54:09 AM · #18 |
| Pitch drops are about the most interesting 'weird' liquids I've come across... |
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06/03/2003 12:02:33 PM · #19 |
Originally posted by Gordon:
Pitch drops are about the most interesting 'weird' liquids I've come across... |
You don't find that kind of long-term commitment to research much any more .... |
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06/03/2003 12:27:32 PM · #20 |
Originally posted by Gordon:
Pitch drops are about the most interesting 'weird' liquids I've come across... |
Talk about patience.....
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