Christmas Trees: Pine and PVC Needles

Generally ice or, rather, water, freezing at a below-zero temperature, increases in bulk when it solidifies. As a child, I was fascinated by a story of a hermetically sealed vessel, filled to the brim with water. If it were allowed to freeze, the water, at the moment of its transformation into ice, would shatter it, no matter how hard the metal from which it was constructed. Actually, of course, the water is no longer ‘water’ when it does it, but has become ice. But this was of no importance to me. What was important to a 6-year old is the image of the exploding bottle, sending shards of glass in every which way. I won’t go into the details of my rather disappointing experiment with an empty wine bottle, water and a cork, but a few weeks later on one especially freezing winter day my dad came home with a frost-bite. He told me that when skin temperature drops low enough, ice crystals can form around and within the cells, freezing tissue and ultimately rupturing cells. I wondered if shards of exploded cell walls also fly in all possible directions.