Pollywogs!

The Aristocrats!

I must have felt it coming…basically, the movie is a straight documentary about a joke, its interesting but unless you are depraved, don’t bother watching. Personally, I thought is was pretty good (see title).

The Mpemba effect
THIS has bugged me for years. I’ve always known it was bullshit, it only works through minutia and details which must specifically occur and which basically take it from interesting to a technicality.

The ‘reason’ my intuition is ‘wrong’:

What’s wrong with this proof is that it implicitly assumes that the water is characterized solely by a single number — the average temperature. But if other factors besides the average temperature are important, then when the initially warmer water has cooled to an average temperature of 30° C, it may look very different than the initially cooler water (at a uniform 30° C) did at the start. Why? Because the water may have changed when it cooled down from a uniform 70° C to an average 30° C. It could have less mass, less dissolved gas, or convection currents producing a non-uniform temperature distribution. Or it could have changed the environment around the container in the refrigerator. All four of these changes are conceivably important, and each will be considered separately below. So the impossibility proof given above doesn’t work. And in fact the Mpemba effect has been observed in a number of controlled experiments

I added the italics and bold. Notice the phrase? Other factors? JESUS FUCKING CHRIST…I have two buckets of water, one is tiny and one is huge. I drop some liquid nitrogen in the small bucket and it froze first. The impossibility proof doesn’t work…give me a break. Of course if you alter the conditions of each volume of water BEYOND the temperature in an extreme enough fashion, it might be able to create specific and controlled conditions where you can utilizes specific processes which might enable the warmer liquid to cool faster than the cool liquid. Lets boil the water, remove the dissolved solids and gasses so that each container has DIFFERENT water in them, fashion a very specific container which maximizes surface area to volume, maximizes convective possibilites and also maximizes evaporation so that the end quantity of water is as small as possible, and then fashion the environmental chamber with conditions which will wick and conduct this extra heat and water vapor away as quickly as possible while constantly introducing new cool and dry air.

Yea, my intuition was waaaay off base…

The full explination, summarized:

If you take warmer water which isn’t the same physically as the cooler water, and put it in a different container in a different environment from the cooler water, under certain specific conditions it might freeze faster.

1) Evaporation: if the hot water evaporates signifigantly more than the cooler water (assuming extremely specific conditions regarding environmental humidity and ambient temperature, surface areas of the water masses, etc), there is less of it and it might freeze faster simply because it has less volume. Very stringent and specific starting conditions?

GIMMICK

2) Dissolved Gasses: if the warmer water has fewer dissolved gasses (due to the fact that various dissolved gasses are liberated on heating and boiling), it might freeze faster due to ‘changes the properties of the water’…but as far as why it might freeze faster, there are only guesses?

Not only a GIMMICK, but a wild guess with no good theory!

3) Convection: water density changes due to temperature, and these different temperature and density portions of a given volume move about (you can watch cold water pour off ice to the bottom of a glass of iced tea which is sorta neat). The ‘hottest’ part of the water would be at the surface, which supposedly would give off the most heat. Further assuming that the surface is the area giving off the most heat, it is possible that the warmer volume will maintain a ‘hot top’ as they call it throughout the cooling process, creating a faster cooling voume of water. Again, you need very specific conditions, specific volumes and container shapes, specific ambients temperatures and humidity creating specific cooling at specific sections of the water…

GIMMICK

4) Surroundings: The warmer water may affect the local conditions of the environment (the example they give is melting frost in the freezer which may increase conduction through the container, which could potentially REALLY increase the cooling to the warmer container).

GIMMICK

Here, all along I thought that this was a scientific experiement with conditions as closely controlled and monitored as possible. Actually, its an experiment where the idea is to create conditions as favorable to the outcome as possible to ‘prove’ that hot water can freeze faster than cold water. Can. Under extremely specific conditions for reasons STILL not fully understood to ‘actual’ scientists who have examined this phenomenom (I’m not terribly excited by the research done to date).

Terribly, terribly misrepresented. Its not counter-intuitive that, when you load the dice, they fall the way you want them to…

I’d want to take cold water, hot water, and do it for myself before I’d sign off completely on it, but under most real world (outside of a kitchen or a lab) conditions I’d say this would NOT happen. That said, I think that ice cube trays and frost free freezers would be an ideal replication of the conditions you’d need to re-create this. Extremely cold and dry, with good air movement to constantly remove the warm water vapor and evaporate the remaining liquid away, with small volumes of water relative to their surface area, typically rounded bottoms and smooth edges for good convective flow, and potentially a little bit of frost on the bottom for the warmer fluid to melt, increasing conductive heat flow while the cooler tray remains insulated by a layer of ice crystals.

Finally, do you need some new wallpaper? One or two of these might make a nice desktop, most are too small tho…
http://visi.com/~reuteler/leonardo.html