Solving a Mystery Behind the Deadly ‘Tsunami of Molasses’ of 1919 | Hacker News Reader

Solving a Mystery Behind the Deadly ‘Tsunami of Molasses’ of 1919

nytimes.com

74 pointspcl20 comments

It's all down to the Reynolds number, which relates viscosity ('sluggishness' of the fluid) n, length scale L and speed v. Re = v*L/n; if this number is low, stuff "happens slowly", if large, stuff "happens quickly".

So if you scale things up, making L larger, you can get fluids that we usually think of as "slow" to act like they're "quick". Like magma: very sticky, but a big enough lava flow can outrun a car.

I wonder how large the pitch drop experiment would have to be before it produced continuous visible flow at room temperature.

https://en.m.wikipedia.org/wiki/Pitch_drop_experiment

Interesting question. It depends of course on the combination of how restrictive the nozzle is (as compared to the width of the column above), and the height of the pitch above the nozzle. If you take the geometry of the pitch drop experiment as fixed, varying only the radius (of both nozzle and column), keeping the pitch height constant, I believe that problem can be solved. Will think about it.

To clarify the question: do you mean that the flow is such that you can clearly see motion, or that the stream of pitch flowing down does not break up into droplets? (The latter depends also on surface tension, the former does not.)

I was thinking such that there is sufficient flow to see motion (say 1 mL/min). I think the boundary between droplets vs continuous flow is a more difficult problem.

Also, as someone in fluid dynamics, I find it interesting that this student project is featured in the NY Times. I mean, it's not trivial, but it's certainly less work and less interesting/innovative than e.g. what the average PhD student produces.

Would it have been in the NY Times if someone at a less prestigious university, led by a less well-connected advisor, had given this project? Somehow I doubt it.

Its also a popular culture reference. Some grad student somewhere is making a discovery about paint that will eventually make Behr a lot of money, but we won't hear about it until the commercials, and maybe not even then.

It paints a bizarre picture of people running from and being killed by waves of gooey, molten sugar, hence a story of interest to the general public, yet one based in science and engineering.

There's an old saying in journalism "if it bleeds it leads." Holds true even in science coverage, and even at the New York Times.

> but it's certainly less work and less interesting/innovative than e.g. what the average PhD student produces.

It kinda sounds like you think work alone should be rewarded rather than outcome?

If PHD students create useless reports after a lot of work then that's their issue. Creating busywork to justify a PHD seems a flawed process.

If PHD students create scientifically great reports then that has no place in the NYT, it's place is in scientific magazines.

If no one has modeled this before (very surprising if true) then this is very interesting news, and pretty good science to boot.

For those interested in this unusual event, the book Dark Tide: The Great Boston Molasses Flood of 1919 chronicles the run-up to the disaster and the enormous court case which followed, in which USIA attempted to blame Italian anarchists for the tank's destruction.

The book also suggests that the behaviour of warm molasses was a likely factor, notably the effect of combining it with the cold molasses already in the tank. So this new research fits perfectly.

I will never describe sluggish software as "running like molasses" again.

Always specify cold molasses, or molasses in winter.

You do realize the event in question occurred during a Boston January?

The molasses itself was fermenting raising its temperature significantly. It cooled and slowed very quickly when it was out of that environment.

It was still molasses in winter. ;-)

I was thinking:

"You might mock the speed of someone moving through molasses but a wall of molasses moving at you is no joke."

Why is it that causes of death like this are simultaneously ridiculous and horrifying? Is it my brain reacting to the horror accounting for the hilarity, or is it just that molasses seems so benign?

One of the issues of Murder Can Be Fun was on the great flood

https://www.amazon.com/Murder-disasters-Boston-molasses-floo...

Someone watched Drunk History last night.

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