Tuesday, 29 November 2011

DECEMBER 8th [Science Comedy Advent Calendar]

December 8th: Ice

Another persistent theme of the festive season is one of snow and other cold-weather phenomenon (if you’re in the Northern hemisphere, that is; conditions are different in the southern hemisphere given the seasonal variations, but I’m not sure to what extent westernised cultural norms overrule logic in this instance)

Every recognisable festive image or icon, be it a space-time defying over-generous bearded fat man, and indoor fir tree, a sleepy picturesque village or anything in a liquid-filled globe that you shake, has to be covered in or at least be in close proximity to some snow. And what is snow? It’s just ice with a lack of discipline.

People can be a bit hypocritical about ice and snow at Christmas, though. They celebrate its image, even going so far as to get imitations of it to decorate with, and they’ll espouse on the joys and merits of children playing in it. But when ice and snow actually does show up, it gets nothing but complaints. This is like name dropping a successful friend or family member to impress other people and get things your own way, but if said person then shows up and asks if they can say with you for a few days, all you do is whinge about the inconvenience, like how you have to pay more for the heating bill and they use up all your salt.

We all like to have a moan about the snow and ice if and when we are confronted with it, that’s almost part of the tradition (of a UK Christmas at least).  But so is gift giving and generosity, we’re told. And yes, ice is annoying; it bursts the pipes, clogs up the traffic, occasionally causes us to fall over and break something, and forces us to wear thick clothes which are impractical and annoying for tasks requiring fine motor control. However, this list of gripes does seem somewhat petty when you consider what ice provides in return; namely, the existence of life on Earth.

Granted, there are probably some sulphur breathing worms on undersea volcanic vents which would dispute this fact, if they were capable of complex cognitive processes and cross-species interaction, which is doubtful. But even they might be indebted to the icy goodness. Life as we know it on Earth wouldn’t be possible without ice doing what it does, and I’m not just referring to the Frozen Planet life, as cool as it may be (pardon the pun).

As you may probably know, ice doesn’t behave like most other solid substances. For one thing, it’s less dense than the liquid form of the substance, water. Ice floats, which is nice. This means it forms a sort of protective, insulating layer on bodies of water in very cold conditions, allowing liquid water to persist beneath, rather than ice sinking and eventually causing the whole mass of water to freeze solid.

As you probably know, liquid water is integral for life to exist, providing an essential medium for pretty much all biological processes to occur in, being known as a universal solvent.

Unlike all the other chalcogens, H2O is a liquid at room temperature. Oxygen, being a bit of a greedy molecule, tends to hog all the electrons in this molecular state, giving it a net negative charge, leaving the poor hydrogen atoms (or ‘protons’ if you prefer) all exposed and naked in their positivity. This means water molecules are ‘polar’, negative on one end, positive on the other, like a magnet, sort of (actually, how do they work?). Essentially this means water molecules are drawn to each other under typical environmental conditions, rendering it a liquid.

But when it’s cold enough, the hydrogen bonds that are so rapidly formed and broken in liquid water become more ‘fixed’, as there’s less energy to break them, feeble as they are. But hydrogen bonds are actually longer than the polar bonds in liquid water, meaning the molecules are further apart, meaning it’s less dense than the liquid.

It’s like getting a box of Lego for Christmas. When it’s in a box, it’s closely packed but all ‘loose’, you can shake it about. When it’s assembled into something, it’s a lot more rigid but also takes up a lot more space. And it’s essentially stable, but takes a certain amount of energy before it reverts to its ‘fluid’ state. With ice, it’s a significant introduction of heat energy, with Lego it’s more of a misplaced foot and a lot of swearing. Either way, the result is the same; rigid but fragile bonds are broken.

It’s a lot more complicated of course, but essentially it goes like this: Ice floats à Life exists.

Also, its inclusion makes everything look ‘Christmassy’, and enhances the quality of various beverages, alcoholic or otherwise. It’s up to you which is more important, but surely that’s enough to overlook a few burst pipes or traffic jams during the festive season?

Twitter: @garwboy


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