Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.

Thursday, June 23, 2022

The domino effect

I find it fascinating how many important discoveries were made more or less by accident -- either because a researcher was looking for something and stumbled upon something else, or because (s)he was just playing around in the lab and noticed something cool.

Here are a few of my favorite examples:

  1. Two researchers, George Beadle and Edward Tatum, were researching nutrition in a mold called Neurospora, and were particularly interested in why some strains of Neurospora starved to death even when given adequate amounts of food.  Their research generated the concept of "one gene-one protein" -- the basis of our understanding of how genes control traits.
  2. Charles Richet was studying how the toxin of a rare species of jellyfish affects the body.  His research led to the discovery of how anaphylactic shock works -- and the development of the epi pen, saving countless lives from death because of bee sting allergies, nut allergies, and so on.
  3. Wilhelm Röntgen was researching the newly-invented cathode-ray tube, which at that point had no practical applications whatsoever.  That is, he was playing around.  He noticed that when he activated the tube, even though it was completely covered, some fluorescent papers at the other end of the room began to glow in the dark.  He had just discovered x-rays.
  4. In 1945 an engineer named Percy Spencer was working with a device called a magnetron that looked like it might have applications in ground-based radar systems.   While messing about with it, he noticed that a chocolate bar in his pocket had melted.   He patented a design that year that we now call the "microwave oven."
  5. Alexander Fleming was something of a ne'er-do-well in the scientific world.  He did a lot of raising of bacteria on plates, and his favorite hobby was to take brightly-colored species of bacteria and paint them on agar media to make pictures.  One day, a mold spore blew in and landed on one of his picture-cultures and spoiled it.  His further investigation of how the mold spoiled the culture led to the discovery of the first antibiotic, penicillin.
  6. Roy Plunkett was working with gases that could be used to quickly cool vessels in scientific experiments, and after one failure he found that the vessel was left coated with a slick substance.  He eventually named it "Teflon."
Stuff like this is one good reason to support pure research.  The criticism "I don't see what possible application this can have" is best answered, "you don't see what possible application this can have yet."  We never lose by finding out more about the universe we live in.  My own opinion is that there's a benefit to knowing stuff even if it never does have a practical use; but even if you're a pure utilitarian, there's no question that putting money into pure research pays back far more than it costs.

This came to mind because of a cool study that appeared two weeks ago in the journal Physical Review Applied about what controls the speed of collapse of a row of dominoes.

[Image licensed under the Creative Commons Nara Cute, Wallpaper kartu domino, CC BY-SA 4.0]

It's hard not to be fascinated by the phenomenon.  For example, take five minutes and watch this amazing record-setting collapse -- of thirty-two thousand dominoes:

Watching this is kind of mesmerizing, but it did bring up two things: (1) I would never have the patience to do this, and (2) if I did, knowing my luck, I'd be somewhere around domino #31,500 and my dog would come galumphing in, knock the whole thing down, and I'd have to start over.

The researchers into the domino collapse phenomenon found that the speed with which the row collapses is dependent upon two things -- the friction between the dominoes and the surface they're standing on, and the friction between one domino and the next one in line.  If you want the collapse to propagate quickly, you want a high coefficient of friction between the dominoes and the surface, but a low coefficient between the dominoes and each other.  The former means that there won't be much slip-back as the domino falls -- as it tips over, the bottom corner of the domino stays put, and the piece pivots around that fulcrum so that most of the energy of the fall is transmitted into the next domino in line.  The latter means that once a domino hits the next one, the slipping of the two surfaces across each other doesn't get "hung up" and lose energy from friction as the top corner of one domino slides across the surface of the next one.

The result lines up pretty well with common sense, but it's cool to have it confirmed experimentally, and that the researchers actually came up with a mathematical model that predicts the velocity of the collapse.

So, what use is it?  We don't know.  Maybe it could be used as a model of systems you don't want to collapse -- like buildings.  But one of the fantastic things about science is when a model in one area of study turns out to illuminate something completely different.  Maybe the mathematical principles of domino collapse rate could be applied to other phenomena that are caused by a phase transition -- a sudden change between one state and another, often caused by a tiny input of energy (like a finger pushing over a single domino).  There are a number of familiar phenomena that involve rapid phase transitions, including earthquakes, explosive volcanic eruptions, breakup of the ice sheet over a river during the spring thaw, and the firing of a neuron once the stimulus threshold is crossed.

Like I said earlier: the beauty of pure research is that we don't know what kind of applications it might have.  With the brilliant minds in the scientific community, you never know where it might lead.  One little paper on a curiosity of physics might trigger new research and go places you'd never expect.

You might even call it...

... the domino effect.


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