Stumping Dr. Science

There used to be a character on National Public Radio who was introduced thus: "Dr. Science – he knows more than you do."  In our household, I am his stand-in, so called because of my propensity for expounding on random scientific subjects to Kim and the dogs during our walks in the Carlisle woods.  It's a toss up which of the three pays the most attention to what I say.

But Kim showed me something this morning, which I have to admit had me stumped: ice cube spikes.  Actually, they look something like little stalagmites but, given that the water is almost pure and that there is nothing dripping from above, and that they tend not to be vertical, they are not stalagmites. Isn't it amazing how the world-wide web can help you find explanations to such phenomena in just a second or two?  Here is a comprehensive and apparently authoritative article called Spikes on Ice Cubes by Professor Stephen Morris of the department of Experimental Nonlinear Physics at the University of Toronto.

I used the qualifier "apparently" above because the world wide web unfortunately does not give us any indication of authenticity on its articles. Rather than get sidetracked, I'll leave that issue for a future blog.  The department's web page suggests that they are all fans of Monty Python, or possibly the Royal Canadian Air Farce.  There is evidently a certain amount of fun to be had while studying nonlinear physics!

But I was reminded yet again of how amazing H₂O actually is.  One of my favorite parts of my Engineering Science course was studying the so-called steam charts: especially the enthalpy-entropy diagram (see below, with appropriate attribution to WikiCommons) and the pressure-volume diagram. But it's the properties of water near the "triple-point" that are most amazing.

For example, imagine what a world would be like if ice just below the freezing point was actually heavier than water (as you'd expect a solid form to be).  There would be no freshwater fish in the temperate or colder zones since as a lake froze, so its top surface (as ice) would fall to the bottom, allowing more water to freeze.  Eventually, the entire lake would be frozen solid until the thaw came.  Good for fish fingers perhaps but not for live fish.

The other thing that I find fascinating is the phenomenon of sublimation, that's to say ice (in the form of snow typically, where there is a relatively large surface area for any given mass of ice) passes directly into the vapor (steam) phase and disappears into the atmosphere.  On some days, you can actually see this happening as there is a blanket of light fog sitting over the surface of the snow.

On the flip side of course, there is the fact that ice melts under pressure – which is good for winter sports enthusiasts, but not so good for those of us who just want to walk down the driveway to get the morning newspaper.

Oh well, you can't win them all.  In fact, as the three laws of thermodynamics have been restated: you can't win, you can't break even, and you can't even quit the game!

But we can still have some fun!