[900295]

Make Instant HOT ICE !

I am doing this experiment for school. When I touch the water in the tray, am I making a stalagmite? Also, what is a supersaturated solution?

[N0help4u]

No that is just a form of crystallization Crystallization of Sodium Acetate from a Hyper-Saturated Solution

A good memory trick to remember the difference in these terms is "Stalagtites hang tight to the ceiling, while stalagmites grow up as a mound from the ground

They are water, calcium carbonate deposits, and usually in limestone caves.

I am sure there is more to both but that is what I know

Stalagmites and stalagtites

[900295]

Also I have no idea what to write for my hypothesis. Like I know its going to work already so what should I write?

[oneguyinohio]

Or stalactite with a "c" is from the ceiling and stalagmite with a "g" are from the ground. I've seen tons of references to stalagtites, and not sure that is accurate? Perhaps it just became acceptable through much use of the term? Any ideas out there? Anyway the tite and might suggest above is good too!

[N0help4u]

I remember my science teacher, many *life times* ago said
Stalagtites hang tight from the ceiling while stalagmites might grow toward the ceiling

[templelane]

THAT'S SO COOL!!

Just so you know a supersaturated solution is one where the solvent has dissolved more solute than under normal circumstances (equilibrium) it can hold. That is why in the experiment it is so keen to crystallise.

I've got handwarmers with that in but I never realised...

[900295]

THAT'S SO COOL!!

Just so you know a supersaturated solution is one where the solvent has dissolved more solute than under normal circumstances (equilibrium) it can hold. That is why in the experiment it is so keen to crystallise.

I've got handwarmers with that in but I never realised...




So when they pour the sodium acetate in the pan, it is becoming a supersaturated solution?

[templelane]

No, it is already a supersaturated solution, that is part of the reason it reacts the way it does.

[900295]

And also, is he using sodium acetate crystals? Because I was looking it up before and no one has done the way he has done it.

[templelane]

Supersaturated
The liquid solution is saturated with respect to sodium acetate (in the form of dissolved sodium ions and acetate ions). However, it is supersaturated with respect to sodium acetate trihydrate (the crystalline form). But unless there is something to activate the crystallization process the solution can remain as it is. Adding a seed crystal of sodium acetate trihydrate jump-starts the rapid freezing process. Dropping a tiny crystal into the solution causes it to rapidly freeze, just like ice crystals can cause supercooled liquid droplets to freeze.

ATMS 101 Summer 2003

Right what that means is the crystallisable chemical has more of it in solution then it would have at equilibrium. However it doesn't have the ability to crystallise until it gets seeded. This is when a particle such as another crystal or a grain of dirt allows the chemical to become an ordered structure.
Seed crystal - Wikipedia, the free encyclopedia

As a side note this is what happens to form hail and certain other types of precipitation.
Hail - Wikipedia, the free encyclopedia

When compounds crystallise they lose energy as they lose entropy (disorder). That is why the reaction is exothermic. This is part of thermodynamics so I won't subject you to the equations unless you want them!

[templelane]

And also, is he using sodium acetate crystals? Because I was looking it up before and no one has done the way he has done it.

Yes the solution is sodium actetate and the crystals are what are formed when it freezes. I think it is a common experiment but there might not be other examples of the exact layout on the internet.

[900295]

So after I cool it in the freezer, it will have created the crystals? I'm sorry I just need this info :P

[templelane]

Yeah if you cool it in the frezer you will definitely have crystals. But as you have seen you can cause it to crystalise just by putting it in contact with other crystals or touching it.