Culturing snowflakes

[Linden.g]

I've been commissioned by Jason Tozer http://www.jasontozer.com to build a system for making snowflakes with the goal to produce a stop motion film of their growth. For a number of years I've been following the Caltech group http://www.its.caltech.edu/~atomic/snowcrystals/designer1/designer1.htm who specilise in the study of ice crystalisation. Jason's request is a great excuss to try it out. I have four weeks to make equipment before Jason arrives to film the action. This is the first step in building the cooling system. The photo shows a peltier cooler cut out of an old Colemans ice box. This can cool down to about -10C when air cooled. I've converted the heat exchanger for liquid cooling and this will fed by an old lab chiller set to -20C. I'm hoping the combination of the two stage system will achieve the desired -40C needed to grow the flakes. The cooling fins which cannot be seen are on the underside of the unit. These will sit in the bottom of a chamber creating a gradient form +40 to -40C. The Caltech example is shown here http://www.its.caltech.edu/~atomic/snowcrystals/designer1/versn2.jpg There is no guarantee that any of this will work but at least there is plenty of entertainment in trying. I'll post up-dates as I go along.

Linden

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Linden Gledhill http://www.flickr.com/photos/13084997@N03/

[rjlittlefield]

Pardon the pun, but very cool! I look forward to seeing how this develops!

--Rik

[ChrisR]

I wonder how well you have to isolate vibrations, how pure your water needs to be, how air-free your water has to be, and that.........

But do have fun!

[Craig Gerard]

Linden,

Fascinating project!

Thanks for the Caltech links.

Looking forward to the updates.

Are you intending to 'mask' the wire?

[Linden.g]

The water doesn't have to be pure because the crystal forms from vapor phase water which come from the +40C evaporation area at the top of the chamber. If you want to make a free falling air column chamber you do need small particles as nucleation centers. I’ll be growing the flake on the tip of an ice needle. This grows from a wire with 2000 Volts potential. Once the needle is formed, which is done at –5C, it is moved down the chamber to –15C and the voltage is switched off. This then makes the ice needle tip grow at 90 degrees and form the flake. I’ve picked up natural snowflakes and they are really strong. So I suspect that you need to control vibration to prevent the ice needle from breaking off the wire support. As for eliminating the support wire or ice needle by masking, this will probably be done post production if needed at all.
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Linden Gledhill http://www.flickr.com/photos/13084997@N03/

[Linden.g]

Some good news, the heat exchanger worked without leaks and the glue held up. It was cooled using a circulating chiller which went down to -15C. I achieved -44C one inch above the cooling fins on the peltier. The system was still going down very slowly so may reach about -45C in this poorly insulated test. On to step three, making the growth chamber!


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Linden Gledhill http://www.flickr.com/photos/13084997@N03/

[Linden.g]

Frost formed in enclosed cooling test chamber. Looks like frost is easy to grow. I'm surprised by how uniform the crystals are even in this crude test.


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Linden Gledhill http://www.flickr.com/photos/13084997@N03/

[Craig Gerard]

Linden,

By coincidence, this evening, I was watching a BBC documentary called 'The Code'. A particular, brief segment with a lead in concerned with Platonic solids and geometry immediately caught my attention, just before a snow flake appeared on screen and the 'Caltech' credit also appeared. The footage features the aparatus outlined in the linked documents of your original post in this thread.

I can't find that particular segment on YouTube, but it is in Episode 2 at the 40min mark. Symmetrical outcomes were elusive.

After that segment the documentary puts its toe in the water of Fractals, starting with Jackson Pollock's paintings and moving on to Mandelbrot and eventually i.



Craig
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To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

[Linden.g]

Thanks Craig, I'll look for that.

The image below shows the circulating chiller feeding peltier cooler on a wooden stand. The stand is designed to bring the viewing window at eye level and enable access for all sides, including from below. Next step is to build the insulated growing chamber.


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Linden Gledhill http://www.flickr.com/photos/13084997@N03/

[Craig Gerard]

Here is Episode 2 'Shapes' from the BBC production 'The Code' on SBS Australia (expires in 8 days (not GMT) from time of writing this message).

Hopefully the video is available to viewers outside Australia?

The Caltech inclusion begins shortly after 30:00 .....

http://www.sbs.com.au/ondemand/video/2197582845/The-Code-Shapes


Craig
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To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

[ChrisR]

I can't get it to run, a white veil with links to Facebook etc obstructs it.

[Craig Gerard]

Chris,

I thought there may be some limitations in regard to viewing regions; but you could try this:?
http://www.sbs.com.au/ondemand/video/2197582845/The-Code-Shapes?from=undefined

Craig
_________________
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

[Linden.g]

I'm having the same problem, with an overlay which stops the play

[Craig Gerard]

It must be a region issue

Craig
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To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

[Chris S.]

Linden, nothing to add--just wanted you to know that I am following your thread with real interest. Fascinating--thanks for letting us have a ring-side seat.

--Chris