[Noisebridge-discuss] First Post: Non-Hg Liquid Metal

[Noah Balmer]

I got curious and looked up gallium's preferred crystal structure.  It will
take on several, depending on temperature and pressure, but the normal
structured is face-centered orthorhombic, meaning there are cells shaped
like irregular cubes with an atom at each corner and an atom in the middle
of each face.  These are a bit like hollow boxes, and so the atoms are
packed less efficiently than when they are free in liquid form.

On Fri, Jun 5, 2009 at 4:19 PM, Noah Balmer <noahbalmer at gmail.com> wrote:

> It is fairly uncommon for liquids to expand when they fuse.  I think
> bismuth does the same thing, and water does, as you mentioned, but don't
> know of anything else offhand.  In the case of water it has to do with a
> crystal structure that requires more space than the amorphous liquid does*.
> I don't know what the mechanism is with gallium.  It has conchoidal
> fracture, which is commonly seen in amorphous glassy solids, so I think it
> may be some other mechanism, but it may just be a very fine grained
> crystalline structure.
>
> -N
>
> *Water molecules are approximately L-shaped.  When they can flow feely
> around each other they can spoon and hook around each other in all sorts of
> ways that increase the density.  When they are frozen into a regular grid,
> the inside of the L is empty, so they are packed less densely.  Pressure on
> ice near the melting point can disrupt the crystal structure and re-liquify
> it, which is one of the reasons ice skates work so well.  A gallium skating
> pond might work too, though gallium loves alloying so much it might just
> dissolve the blades (it dissolves aluminum readily, don't bring it on a
> plane!) , and in its liquid form it's kind of sticky.
>
>
>
> On Fri, Jun 5, 2009 at 3:48 PM, d p chang <pchang at macrovision.com> wrote:
>
>> Noah Balmer <noahbalmer at gmail.com> writes:
>>
>> > I'm surprised to see it stored in a glass vial in that image
>> > though, because it expands by a few percent when it solidifies, and
>> > will often break rigid containers.
>>
>> wow. i thought water was 'weird' that it expanded when it became a
>> solid. am i just mis-remembering something or is this actually common?
>>
>> \p
>> ---
>> I know that you believe that you understood what you think I said, but I
>> am not sure you realize that what you heard is not what I meant.
>>                - Robert McCloskey
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.noisebridge.net/pipermail/noisebridge-discuss/attachments/20090605/b4e6afb5/attachment-0003.html>