• Fleur_@aussie.zone
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    1 day ago

    Volume of glass

    Volume of hazelnuts (median)

    Packing efficiency of spheres in a cylinder

    Do some math

    Be wrong by an order of magnitude because all the little hazelnuts are concealing one giant one

  • Gustephan@lemmy.world
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    2 days ago

    Vibes. I look at it and try to guess and submit a number within 5 or 10 seconds. It may not be as accurate but I feel like I get more benefit training my ability to estimate at a glance than I do training my ability to do math and spatial reasoning assisted by math. Im already really good at math and math assisted spatial reasoning

  • ornery_chemist@mander.xyz
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    2 days ago

    Roughly a truncated cone with diameters ~7 nuts and ~9 nuts, and the cup is ~12 nuts high (loose guesses, it is hard to tell due perspective and nuts of different sizes). Throw in an extra layer to account for the heap at the top (which is a dome taller than 1 hazelnut, but treating it as a shorter but full layer should give some error cancellation) to give a height of 13. The volume of a truncated cone of those dimensions is ~657 cubic hazelnut diameters. Random sphere packing is 64% space-efficient (though wall effects should decrease this number) giving a total of 420 nuts (nice).

    Multiple edits for clarity and typos.

    Answer

    This ends up being about 5% lower than the true answer. I’m surprised it’s that close. This is in the opposite direction from what I expected given wall effects (which would decrease the real number relative to my estimate). Perturbing one of the base diameters by 1 nut causes a swing of ~50, so measurement error is quite important.

  • anyhow2503@lemmy.world
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    3 days ago
    1. Set lower bound by counting how many are visible in the photo
    2. Grow disinterested
    3. Guess some number above the result from step 1
  • jh29a@lemmy.blahaj.zone
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    2 days ago

    I counted 11 down and 7 across, so I assumed the radius is 3.5 hazelnuts and the height eleven, making pi r² h = 423 hazelnuts. that is, if they haven’t snuck in any walnuts.

  • rowinxavier@lemmy.world
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    3 days ago

    Start with the bottom, count how many are visible on the lowest layer. This gives you half the circumference of the lower end.

    Repeat for the highest part of the cup that is still cup, not above the line.

    Multiply each of these by 2 and you have the circumferences of each end of the cut cone.

    Rearrange the circle area formula to get the radius from circumference and you have the radius of each end of the cone.

    Now use the cut cone formula to calculate the volume in terms of hazelnuts.

    Next, take the radius of the top circle and estimate how far above that the highest nut is. Use whatever formula seems more appropriate, in this case maybe just a right angle triangle formula with a full rotation, to estimate the volume of the top.

    Sum that together with the conic volume and you have a good estimate.

    My estimate, at least 3 hazelnuts.

    Good luck

  • TheCriticalMember@aussie.zone
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    3 days ago

    For a tapered section like that, you could estimate bottom and top layers and then average them. Then estimate height and multiply. You’d want to include an overlap factor as the roughly spherical nuts would settle in between each other somewhat. I’d imagine there’s some accepted value out there for that.

    • CmdrShepard49@sh.itjust.works
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      3 days ago

      This is what I did. Roughly 5 wide at the bottom and 7 wide at the top or roughly 12 nuts per layer average. Then the stack appears to be about 12 nuts high so 144 total and maybe round up to 150 since it’s heaping at the top.

      Edit: I didn’t initially see OP’s link to the site and I call complete bullshit on that ‘correct’ answer without seeing them poured out and counted on video. According to it, my answer is off by several hundred.

        • CmdrShepard49@sh.itjust.works
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          3 days ago

          Only when it jives with a sensible guesstimation.

          Without outright spoiling the answer, according to the site, roughly every visible hazelnut in the image makes up just 16% of the total. If my guess of 12 layers is roughly accurate, every visible hazelnut only makes up two layers of the total which doesnt seem correct.

          Considering this is a user submitted puzzle with zero verification (as far as I know), the simplest answer is that they gave a fake/incorrect number.

      • brian@lemmy.ca
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        3 days ago

        Not sure where you’d land at 12 nuts per layer on average. If you go off 5 nuts “wide” as your diameter you’d end up with at least 20 nuts at the bottom layer (area = π(5/2)² = 19.6).

        • CmdrShepard49@sh.itjust.works
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          2 days ago

          I did 5 wide at the bottom and 7 wide at the top. 5x2 and 7x2 =24/2 (average) = 12 per layer. I now see how this isnt exactly correct as it’s a circle but the ‘proper’ answer puts it at 36 per layer which doesnt seem correct either.

          • brian@lemmy.ca
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            2 days ago

            Ah, but you’re calculating the area, so it would be length * width, not just multiplying by 2.

            So you’re looking at 25 at the bottom and 49 at the top, making your average 37 per layer.

  • Pulptastic@midwest.social
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    2 days ago

    The cup is about 13 hazelnuts high. The top circumference looks like it could hold about 24, the bottom about 20, so I’ll average that to 22.

    13*22=286

  • Siegfried@lemmy.world
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    2 days ago

    Imagej

    In arbitrary units, I need in pixels estimations for:

    Height of the vase H

    Top diameter of the vase Dt

    Bottom diameter of the vase Db

    Mean diameter of a hazelnut Dh (measuring a few of them)

    Packaging factor F… something arround .6? I’m sure there is a better way of estimating it. Like counting air and hazelnut areas on the image but I’m not sure how to correlate 2D to 3D in this case.

    The volume of the vase is Vv (H,Dt,Db)

    The volume of a single hazelnut Vh (Dh)

    N = Vv F / Vh

  • m0darn@lemmy.ca
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    2 days ago

    I did

    V=pi×r²×h

    and estimated:

    r=4 (from some at the top left)

    h=12

    This gave 603. The link said too high, so realized I’d neglected packing factor. Google said that spheres typically pack at 64% efficiency, so I guessed 386. Too low.