Recently I spent the day making ice crystals in the kitchen. The relatively simple experiment requires little more than a plastic bottle, some dry ice, and a lot of patience!
In short you surround the bottle with dry ice to lower the temperature to the crystal forming region ( 0 to -20), have a source of water within the bottle – a wet sponge – to saturate the air within the bottle, and a point on which the crystals can form – Here I used a fishing line running through the middle of the bottle.
At the 10 minute mark the first signs of crystals were materialising
A further 10 minutes into the experiment and proper flakes began to form
At the 45 minute mark better crystals had formed on the sides of the growth chamber than on the nylon thread.
An hour into the experiment and the crystals had started to grow radically and lost much of the symmetry found in the earlier stages. I put this down to the varying conditions brought on by continuously opening the chamber to take pictures, so i decided to repeat the experiment under more controlled conditions and left the grown chamber untouched for an hour. This allowed the development of a nicely symmetrical fernlike dendrite branch (nearly 1cm long!!):