It is that time of year when the hand of Winter is felt upon the land and we turn our thoughts to such pursuits as skiing, hot chocolate and, of course, making snowballs. But this is an art not to be undertaken lightly, for there are arcane and obscure techniques to be used. I shall reveal one for you here today and you will never add a snowflake, nor even a drop of water to make it.
First, you require a Dewar. Use it for a while as a vacuum trap, with plenty of dry ice and a little isopropanol. Keeping topping it up with dry ice regularly. Do this for a while, until your extensive experience tells you it is time to move to the next phase. A sign that it is ready is when you have trouble getting the trap out of the Dewar when you want to empty it. This is an art that requires great patience.
Next you let the trap thaw and remove the trap, preferably without breaking it (if you can). The dry ice has gone, but a large block of ice is within, ready to form your perfect snowball.
Now you add some acetone, as the snowball won’t come out without some help. I don’t recommend breaking the Dewar. Let that sit for a short while then drain out the acetone (save it for making cold baths later).
If you have done it right, the snowball shall emerge, perfectly smooth and rounded. Is it not both beautiful and awe-inspiring?