Voy Por Ustedes

It's so cold at the moment it got me to harking back to something a dude said to me once when I was mooching around Niagara Falls about ten of our Earth years ago. I was not sure at the time if he was pulling my lariate, but he absolutely insisted that Niagara Falls froze once. You daft Canadian fucker I said, that's not possible. I looked around for a physicist to help me out but couldn't find one, so in the interests of Anglo-Canadian relations I eventually relented and I told him I believed him, but of course I had my fingers crossed behind my back as I spoke.

After some research it appears that photographic evidence does indeed seem to prove that in 1911 the falls did freeze, but their authenticity is in doubt. I'm still sceptical. I'm sure the volume of water is too great for it to freeze completely. Something like 650,000 tonnes a minute of water spill over the horse-shoe section and even in Canada the tempretures can't surely drop low enough to freeze such a volume of water. Surely?

It's a common misconception that moving water will not freeze, but it is interesting to think a bit in detail about the factors involved no? At least I think it is. It's more interesting than watching Blackpool v Wolves anyway. Liquid water, like what a river is and that, is by definition, above the freezing point of water. In order for it to freeze, it has to lose some of its molecular energy and get its temperature down to the freezing point.

Depending on the volume of water, the time it takes to freeze will vary. Freezing point will be determined by a combination of how much above freezing it starts at and how quickly it can lose heat to the outside environment, oui?

That rate of heat loss will depend on lots of things, including the outside temperature, how much surface area is exposed relative to the volume of the water, whether there is wind outside to help bring fresh cold air to the water's surface, etc etc. More over people, since to get water to freeze you need to cool it to 32 degrees but then still remove a bit more heat energy - the so-called latent heat of fusion - to get it to go solid. Solid I tells ya.

"Freezing requires that the initially very disordered water molecules get all lined up into a neat, orderly crystal, and if there are any contaminants dissolved in the water (as is often the case outdoors), they will get in the way of ice crystals forming and the freezing point will go down. Motion of the water can also interfere with the formation of crystals, and this is especially the case if the flow is irregular and turbulent, so still colder temperatures may be required." -- A physicist dude

So in real terms, any amount of water will freeze if it gets cold enough. But Niagra Falls is so huge that the tempretures would need to be something similar to the conditions between Mother Teresea's thighs.

But though, but, Niagara Falls in 1911 was much much smaller than it is today as the water has eroded away the rocks so quickly - apparently it has ventured something like ten miles inland in the last 100 years. So it may be true. I'd like to think it's true. So I choose to believe it.

I therefore apologise to the chap who initially told me about the 1911 freezing for doubting him and calling him a silly twat under my breath.