is jello a solid or a liquid?

[irishcandie]

so recently i was eating some pudding and the thought came across me, is jello a solid or liquid? I figure that pudding is a liquid right, but what about jello, it is so jiggly but it isnt quite solid but not quite liquid, im very curious about this
what do you think?

[General Awesome]

A liquid's shape is determined by the shape of the container it fills.
What you got there is a solid.

(I'm sure there are other properties of liquids/solids that would also prove that, but I'm kinda tired)

[whateverfloats]

Amorphous solids? I'd actually consider both pudding and jello to be liquids with high viscosity, but I'm not 100% sure about this.

[VorpalNeko]

A highly viscous liquid would just just flow very slowly. Jello can store elastic energy through shear stress and returns to its original shape when thus stressed (experiment: take a jello cube and push the top sideways, keeping the bottom stationary), which is the key defining characteristic of being solid.

It seems to me that the confusion comes from it being a colloidal suspension of a liquid in a solid (gelatin)--it's not a crystalline solid by any means, and by mass, it's mostly liquid.

[whateverfloats]

VorpalNeko

A highly viscous liquid would just just flow very slowly. Jello can store elastic energy through shear stress and returns to its original shape when thus stressed (experiment: take a jello cube and push the top sideways, keeping the bottom stationary), which is the key defining characteristic of being solid.

Can't water do this too? If you watch a water droplet through a microscope you can see it rebounding. And water, despite it's usual properties, is all liquid.

[Vryko Lakas]

whateverfloats

VorpalNeko

A highly viscous liquid would just just flow very slowly. Jello can store elastic energy through shear stress and returns to its original shape when thus stressed (experiment: take a jello cube and push the top sideways, keeping the bottom stationary), which is the key defining characteristic of being solid.

Can't water do this too? If you watch a water droplet through a microscope you can see it rebounding. And water, despite it's usual properties, is all liquid.

I suspect water behaves that way through surface tension rather than solid structure.

[CatLuvr83]

irishcandie

so recently i was eating some pudding and the thought came across me, is jello a solid or liquid? I figure that pudding is a liquid right, but what about jello, it is so jiggly but it isnt quite solid but not quite liquid, im very curious about this
what do you think?

I think you're Jessica Simpson.

Pudding is totally a solid as is jello.


Duh. Major duh.

[VorpalNeko]

whateverfloats

VorpalNeko

A highly viscous liquid would just just flow very slowly. Jello can store elastic energy through shear stress and returns to its original shape when thus stressed (experiment: take a jello cube and push the top sideways, keeping the bottom stationary), which is the key defining characteristic of being solid.

Can't water do this too? If you watch a water droplet through a microscope you can see it rebounding. And water, despite it's usual properties, is all liquid.

But that's not shear, which is by definition tangential to the surface. Perhaps considering where surface tension effects come from will make it clear that they can''t withstand shear stress. Inside the liquid, intermolecular forces tend to cancel out, as any directions "looks like" any other (in terms of the distribution of molecules) on that scale. But at the surface, one direction has molecules, whereas the other does not, leading to an imbalance. Voila: surface tension.

But that's an imbalance in the directions perpendicular to the surface (out vs. in). Tangent to the surface (i.e., in directions that "locally stay within" the surface), the distribution of the molecules will be about the same on average, and hence its effects will also tend to cancel out. Thus, surface tension does absolutely nothing for shear.

[Pflibbitz]

General Awesome

A liquid's shape is determined by the shape of the container it fills.
What you got there is a solid.

(I'm sure there are other properties of liquids/solids that would also prove that, but I'm kinda tired)

The definition of a solid is that it has a specific melting point. Below a certain temperature it is consistently a solid and above that specific temperature, it is consistently a liquid. For Water, that is 0 C or 32 F.

There are objects which appear to be solid but do not have a specific melting point which, as they are heated, just become more and more pliable as the temperature increases.

The classic example of a "Super Cooled Liquid" is GLASS! It is forever a liquid, even though it appears to be a solid. There is no temperature below which it is always a solid or above which it is always a liquid, but glass just flows at increased speed as the temperature is increased.

Find an old house with original panes of glass and you will see "Ripples" in the surface as you look through the glass. In essence, over time, the glass has flowed, ever so slowly, creating a variance in the thickness and molecular distribution of the pane of glass.

The colder Jello gets, the more solid it appears, and the warmer it gets, the more viscous is gets, so it is perhaps another Super Cooled Liquid.

But of course, there is another aspect which might be considered. Perhaps Jello is neither a Solid or a Liquid but a Suspension which alters the properties of the liquid it is suspended in.

[Vryko Lakas]

Pflibbitz

Find an old house with original panes of glass and you will see "Ripples" in the surface as you look through the glass. In essence, over time, the glass has flowed, ever so slowly, creating a variance in the thickness and molecular distribution of the pane of glass.

That's actually not true, and the distortions you see are due to the various manufacturing methods used to make glass into panes, methods which changed with time, geography, and expense. It would take far longer for solid glass to "flow" visibly than we've been making transparent glass for.

[Pflibbitz]

whateverfloats

Amorphous solids? I'd actually consider both pudding and Jello to be liquids with high viscosity, but I'm not 100% sure about this.

I think you have that backwards. The higher the Viscosity of a liquid, the more rapidly it flows.

Hence, I believe you should have stated the reverse, or, "I'd actually consider both pudding and Jello to be liquids with LOW viscosity....."

[Pflibbitz]

Vryko Lakas

Pflibbitz

Find an old house with original panes of glass and you will see "Ripples" in the surface as you look through the glass. In essence, over time, the glass has flowed, ever so slowly, creating a variance in the thickness and molecular distribution of the pane of glass.

That's actually not true, and the distortions you see are due to the various manufacturing methods used to make glass into panes, methods which changed with time, geography, and expense. It would take far longer for solid glass to "flow" visibly than we've been making transparent glass for.

Because of the properties of glass and refraction, the variations can be very small and yet produce easily visible results. Also, the ripples are most frequently horizontal while using your analogy, there must be as many panes of glass the "manufacturing defects" in all directions.

As for your reference to a time frame for glass to flow when it is oriented in a vertical direction, I'm not sure if that has been determined but there might be citations somewhere out there.

Also, your statement about "Solid Glass" is contradictory because Glass is not a Solid but a SUPER COOLED LIQUID

[Vryko Lakas]

Wiki says it so it must be true

[Pflibbitz]

Vryko Lakas

Wiki says it so it must be true

And Pluto is not a PLANET?????

I'll stand by my original statement and IMHO, Super Cooled Liquid was the scientific opinion when I was in school, so in my mind that is the way it will remain.

Amorphous Solid is too much of a "Marble Mouthed Phrase" for me!!!!!!!!!


And NO, the Earth is not FLAT, just because before technology existed, that was the only way they could think of it.

[Vryko Lakas]

Pflibbitz

Vryko Lakas

Wiki says it so it must be true

And Pluto is not a PLANET?????

I'm actually rather cool with that one. I mean, Pluto and Charon shared a common barycenter that was external to either's body. That alone probably should have been a case against it.
Although if things had gone the other way, I would have also welcomed the addition of planets Ceres, Eris, etc.