Hot Ice - One for PalmerC to explain

Rory

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Wow that looks fun... So where does one get Sodium Acetate palmerc?

Oh, also what counts as "touching it"? Obviously not the plastic/acrylic container or glass it was in, but the lid or whatever it was poured onto does seem to "count".
 
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Interesting, never seen this before...Would make a cool party trick.

But all that is really happening is that you have a supersaturated salt solution (sodium acetate works here because one can dissolve plenty in very little water 10g in 6ml of hot water).

When it is cold the solution is "unstable" and really overloaded with ions. When you touch it, dirt/whatever from your finger creates nucleation sites for crystal growth to begin and obviously it is like a chain reaction.

This is also why they say don't pour over the undissolved sodium acetate before cooling as this would cause the crystallisation to begin in the freezer. And allthe glasses/containers woudl need to be very clean as well - no dust.

To bring the topic back to reefkeeping, this is similar to why the addition of powdered aragonite or calcium carbonate can aid coralline growth - creates nucleation sites for the start of coralline growth.

Your friendly mad scientist,
Clinton
 

Rory

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So is that why when millepora touches someones tank it goes pink then?
 
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Cool.. thanks for the explantation Clinton, and for finding a Reef Reference in it :D

It would explain Mille as well. His body is super saturated in Salt from all the time he spends surfing while the rest of us work.. :lol:
 
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It's fun...Solving Chem-MYSTERY !!!

Wow that looks fun... So where does one get Sodium Acetate palmerc?

Oh, also what counts as "touching it"? Obviously not the plastic/acrylic container or glass it was in, but the lid or whatever it was poured onto does seem to "count".
I've done this a few times.

..some answers

1) Sodium acetate is easily bought from chemical supplies,a relatively "safe" salt so, no issues with availability.
[AKA E262, food preservative]

Besides those "handwarmers" uncommon in SA, it's used extensively in textile, tanning, print and food industries.

If you smaak, you CAN MAKE YOUR OWN sodium acetate AND "hot ice"
-'pure enuf'-
it WILL WORK, is cheap, and below ingredients are domestic kitchen standards...heheh

Acetic acid (8%), if unavailable, then spirit vinegar(white is best), and some "Bicarb" are all you need besides 2 clean saucepans...some glass tumblers, and ice-tray, but polystyrene trays work too !!!

Method, avail from me, in good Chem texts or online.
>Insert Disclaimer HERE< :whistling: :wave2:

2) Keen eyes there, huh Rory ???
You maybe noticed the CHEAT !!!???

The dude doing the demo, has a grain on his fingertip, BEFORE TOUCHING THE SURFACE.

It's SEED CRYSTAL !!!
Required for RAPID proliferation of crystallization.

Without a seed crystal to act as a template for formation of a crystal lattice, crystallization is very slow and a solution can be supersaturated for a long time.

(CaCl2) Calcium Chloride, favoured ionic Ca source for reef aquaria ALSO yields heat when dissolved ...another exothermic reaction !



BTW All supersaturated salt solutions can't be employed for similar dramatic effect, it HAS to be a hydrate form of solid with Phase behaviour, in this case Sodium acetate trihydrate.
 
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Another very cool explanation there Obi Wan.

I did not spot the seed crystal which is why I suspected dust or something. I also think the crystallisation process shown was speeded up quite a lot, pretty sure it does not happen in 2-3 seconds.

And your method of producing sodium acetate. Elegantly simple.
 
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Interesting Liaquat !!! I can see you were the one sneaking bunsen burners off to your room at campus.. lol
 

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