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Christmas Cheer Science

How One Man Proved No Snowflakes Are Alike (cnn.com) 45

CNN shares the historic close-up snowflake photos of Wilson Bentley, the first person to capture the details of the individual "snow crystal" ice that makes up snowflakes.

It was 1885, just 69 years after the invention of the camera, and after years of trial and error, "He went on to photograph more than 5,000 of these "ice flowers" during his lifetime — never finding any duplicates — and the images still mesmerize to this day." Every snow crystal shares a common six-sided or six-pointed structure — it's how frozen water molecules arrange themselves — but they will always vary from one another because each falls from the sky in its own unique way and experiences slightly different atmospheric conditions on its travel down to earth. Some of their arms may look long and skinny. Others may appear short and flat or somewhere in between. The possibilities are endless and fascinating....

"He had the mind of a scientist and the soul of a poet, and you can see that in his writings," said Sue Richardson, Bentley's great-grandniece who is vice president of the board for the Jericho Historical Society. "He wrote many, many articles over the years for scientific publications and for other magazines like Harper's Bazaar and National Geographic. "He also kept very detailed weather records and very detailed journals of every photograph that he took of a snow crystal — the temperature, the humidity, what part of the storm it came from. He kept very detailed information, and then these weather records that he kept and the theories that he developed about how snow crystals formed in the atmosphere, those were proven true...."

It wasn't easy, however, to get those snow crystals on camera. It took almost three years, Richardson said, for Bentley to figure out how to successfully photograph one — which he did just a month shy of his 20th birthday. The first obstacle was figuring out how to attach the microscope to the camera. And then there was the challenge of getting each crystal photographed before it could melt away. "He worked in an unheated woodshed at the back of the house. He had to," Richardson said. "And the microscope slides, everything, had to be an ambient temperature or they'd melt" the crystal....

A children's book about him won the Caldecott Medal in 1999.

Bentley never had formal education, according to his grandniece (who grew up hearing stories about this famous ancestor). One says that when Wilson Bentley was given an old microscope at age 15, "The first time he looked at a snow crystal under it, he was hooked. Just the beauty, the intricate detail. He was totally hooked."
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How One Man Proved No Snowflakes Are Alike

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  • Let's take pictures of 5000 different people, and see, no two looked alike. Hence, "proved" twins do not exist.

    Also, no rocks are alike, no grains of sand are alike, etc, etc.

    • Well, the primary statement is a negation, so you would have proved a negative to prove it.
    • by tragedy ( 27079 ) on Sunday December 25, 2022 @09:16AM (#63156652)

      Exactly, if you examine them closely enough, no two things in the history of anything have ever been 'alike' because of differences at the molecular, atomic, and quantum levels. However, if we allow for variances in accuracy and precision at those levels to the degree that the term 'alike' has meaning and there are things that are 'alike' then there certainly are snowflakes that are alike. Snowflakes have branching, fractal-like complexity and that allows for a tremendous number of configurations, with complexity increasing as the snowflake gets bigger and when the conditions are right to allow more branching. The thing is, the conditions are not always right. A lot of snowflakes are just basic plates or prisms without a lot of branching. Obviously there are many of those that are 'alike' if you do allow for minute differences. Or very basic branched snowflakes. Basically you can only really say that no two snowflakes are alike (when you allow for 'alike' to include a given amount of molecular/atomic/quantum variance) if you make special rules for bare minimum complexity and size it needs to have to be a "snowflake" Otherwise, depending on complexity, in a given snowstorm, you have massive numbers of snowflakes that are alike.

      Also, the article title is obvious nonsense. You can't "prove" that no two snowflakes are alike with that small a set of samples compared to how many snowflakes there are/have been. It's a load of bunk. The snowflakes pictures are neat, and they demonstrate the high degree of variability, but they don't prove absolute uniqueness.

      • No mod points, but I enjoyed your analysis of this nonsense. Merry Christmas!
      • Since we are being technical, I am interested to know the ways in which two electrons would be non-alike (excluding location and velocity as those aren't relevant to the commonsense use of the word 'alike).

        I am of the understanding that most if not all electrons are identical to the point of being non-differentiable, which would contradict your statement that "no two things in the history of anything have ever been 'alike'". But I would be very interested in being proven wrong with a detailed description o

        • by tragedy ( 27079 )

          I was including relative position and velocity within the structure as something to measure. I don't see any reason to exclude those. So, suppose you're looking at the atoms at the very tips of two of the points of the arms of two "identical" snowflakes. You simply can't say that the atoms are aligned with the same symmetry in both structures since you can't say if the atoms are in the same spots/moving in the same direction moment to moment That's at the quantum level. Above that, unless you're at absolute

      • Also, the article title is obvious nonsense. You can't "prove" that no two snowflakes are alike with that small a set of samples compared to how many snowflakes there are/have been. It's a load of bunk. The snowflakes pictures are neat, and they demonstrate the high degree of variability, but they don't prove absolute uniqueness.

        It would perhaps be interesting, albeit also not a proof, to enumerate the (hierarchical) degrees of freedom for snowflake structures of a given size, then to probabilistically estimate the number of snowflakes needed to achieve a low probability (say 1%) of finding two exact replicas, and finally to determine how many years of snowflake production based on historical norms are needed to achieve that low threshold. If that low threshold would require a very large number of years (e.g., the number of years

    • The whole concept is stupid. Different initial conditions can end up giving the same result, given enough samples - and there's lots of snowflakes out there throughout history. It's pretty much inevitable that there would be at least 2 alike.
      • Maybe they have some microstructure in common, but snowflakes are large enough to be incredibly complex. The number of possible permutations makes it such a large number of possibilities that even in a massive universe across billions of years and all of the flakes that have fallen, no two have been alike because the odds that it happened even once are so low it's effectively zero.

        It's similar to the notion that each time you shuffle a deck of cards, it's almost assuredly an order that has never been obs
        • Problem is, the number of permutations is far less than you'd think. I remember reading an article claiming that the number of permutations in tic-tac-toe is 9x8x7x6x5x ... which is false logic. X on square one, O on square 2, and X on square three ends up being the same X on square 3, O on square 2, X on square 1. So their "over a third of a million possible combinations" was actually 2,000. Not counting rotations and mirror images, and impossible combinations such as XXXOOOXOX.

    • by rastos1 ( 601318 )
      fingerprints?
  • by Sleeping Kirby ( 919817 ) on Sunday December 25, 2022 @08:54AM (#63156620)
    https://apnews.com/article/87d... [apnews.com]

    I feel like the idea has been taken too far:
    https://www.forbes.com/sites/s... [forbes.com]

    According to the Guinness book of world records, Nancy Knight, a scientist at the National Center for Atmosphere Research, serendipitously discovered two identical examples of snowflakes while studying snow crystals from a storm in Wisconsin in 1988, using a microscope. But when Guinness certifies two snowflakes as identical, they can only mean that it's identical to the precision of the microscope; when physics demands that two things be identical, they mean identical down to the subatomic particle! That means:
    You need the same exact particles,
    In the same exact configuration,
    With the same bonds between them,
    In two entirely different macroscopic systems.

    Which, is impossible to the point where the snowflake part is moot. Nothing in the universe can have the exact same bonds and configurations, let alone the same exact particles.

  • by Anonymous Coward

    And the microscope slides, everything, had to be an ambient temperature or they'd melt

    It's amazing what people can figure out without a formal scientific education. Why oh why isn't it enough that he took pictures of natural beauty? Do you have to embellish his achievement with unjustified claims? He did not prove that there aren't two snowflakes alike, and figuring out that you have to work with tools below freezing isn't the hard part of the task, is it? Just enjoy the pictures.

  • Probabalstic (Score:4, Interesting)

    by John Allsup ( 987 ) <slashdot@chal i s q u e.net> on Sunday December 25, 2022 @09:13AM (#63156642) Homepage Journal

    Like chess games. They start similar to stuff that's already been played, but with diminshing probability will they duplicate a previously played game exactly.
    Or consider hashes: hash collisions are mathematically inevitable, yet we haven't seen even one for SHA256.

    You can't prove that two snowflakes will logically always be different (there is no physical mechanism whereby one growing snowflake can check to see if it's making a shape that's already been made), merely that under sensible assumptions, the probability of two flakes being identical is astronomically close to zero.

  • But all snowflakes *are* alike. What they are not, is identical.

  • by meerling ( 1487879 ) on Sunday December 25, 2022 @09:50PM (#63157616)
    A researcher (pre 2000) actually did find two snowflakes that were the same.
    Well, they looked alike under the microscope and had the same crystalline fractal pattern.
    But like any other comparison, if you go down deep enough, maybe even to the atomic level, there will be differences.
    So the whole no two snowflakes are alike is obviously correct if you go to extreme precision, but at the human level, even with a common optical microscope, you can find matching snowflakes, even if your odds are abysmally small.

    And if anyone was wondering why any sane researcher would be checking out snowflakes, there are lots of relevant research dealing with water and it's many forms, as well as crystallization as well. These and other such research aren't just for giggles, it actually helps with various pure science as well as commercial and industrial work as well. It's prpobably not going to get an iGNobel, or a Nobel prize either, but it's still valuable work.

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