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Draw an iceberg and see how it will float

joshdata.me

388 points by mabynogy 2 years ago · 62 comments

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xg15 2 years ago

Got a bit frustrated because I couldn't get anything except a flat surface above the water, then read the tweets below and realised that's the entire point:

https://threadreaderapp.com/thread/1362557149147058178.html

(Many thanks to Elon for making it impossible to read more than the first tweet on x.com without an account...)

  • ajb 2 years ago

    Here's a non-flat one:

    https://imgur.com/a/7KANxOn

    Very unlikely to occur in nature I guess :-)

    • xanderlewis 2 years ago

      https://ibb.co/ZLYxr4x

      Sometimes to innovate you have to think like a child — or a teenager.

      • rvnx 2 years ago

        Make sure to patent it before they use this as base design for the Cybertruck^2

      • isoprophlex 2 years ago

        Nice tip on that iceberg

      • barfbagginus 2 years ago

        I was about to post something similar. But you nailed it before I could swing my own hammer, to use a figure of speech.

      • barfbagginus 2 years ago

        I was about to post something similar. But you nailed it before I could swing my own hammer, to use a figure of speech.

    • manwe150 2 years ago

      That works, but my personal favorite is drawing something like 2 half notes, connected, since a bridge shape seems to maximize the height*width of iceberg visible above the water. There is nothing to stop you from just adding a wide flat plane to the top of your spike either though to add more flair!

  • HarHarVeryFunny 2 years ago

    My mental model is of each side (think left/right in 2-D) of the iceberg competing with the other side to float to the surface by rotating the iceberg around it's center of gravity. The only stable positions are where these left/right rotational forces are balanced.

    If an iceberg is currently floating in a vertical orientation where more of it's mass to one side of it's center of gravity (bottom half) is underwater compared to the mass on the other side (top half), then it's going to tend to rotate until both sides are equally above water, so (depending on mass distribution) horizontal orientations are likely to win over vertical ones.

    Of course an iceberg could balance vertically, but that's like balancing a pencil on your finger - not the most stable, and any disturbance (such as the initial calving event) is likely to rotate it into a more stable horizontal orientation.

    • Sharlin 2 years ago

      That’s exactly it. An iceberg can’t stay "vertical" for the exact same reason that a pencil can’t stay vertical. Even if perfectly balanced, the equilibrium is unstable.

  • kazinator 2 years ago
  • JadeNB 2 years ago

    > (Many thanks to Elon for making it impossible to read more than the first tweet on x.com without an account...)

    https://threadreaderapp.com/thread/1362557149147058178.html

  • WhitneyLand 2 years ago

    Try something that has no flat surfaces. For example a five pointed star.

  • RobertRoberts 2 years ago

    I drew an equilateral triangle and it floats flat on top.

  • furyofantares 2 years ago

    Hexagons work

joshdata 2 years ago

Author here. Glad to see this making the rounds again after a few years.

Go science! Support your local climate scientist!

  • cscurmudgeon 2 years ago

    Great education simulation! Thanks for working on this.

    Curious about this: I am hitting a boundary-condition like behavior drawing a straight line at a 45 degree angle similar to the sibling comment.

    Curious if it is due to physics or due to the simulation.

  • _Microft 2 years ago

    This is very cool.

    I found shapes that do not work well with the simulation: a very wide and narrow shape (like a needle) oscillates wildly and does not seem to stop or to even slow down.

  • jackspratts 2 years ago

    nice job. these simulations are 2d. does 3d make a difference? i'm almost about to start carving styrofoam to see.

    - js.

sinuhe69 2 years ago

I got a design which wobbles infinitely! :D The clip was live recorded, not looped.

https://streamable.com/0a9zmb

madcaptenor 2 years ago

A version which has some preloaded shapes and shows the forces explicitly, inspired by the same tweet: https://engaging-data.com/iceberger-remixed/

This is all from 2021 and I feel like I’d seen this prior to that but I can’t find it.

sa46 2 years ago

The HTML source code is a well-commented, fun read.

- There's a fair bit of math to model drag, mass, and density using the specific gravity of ice and seawater (with tweaks to make it more realistic for 2d).

- Try adding a polygon that overlaps itself (self-intersects).

- You can paste images! The code traces the image and picks the most complex polygon.

GeorgeRichard 2 years ago

This is great fun--and accurate. My lettuce floated just like the picture I drew when I tested it in the bath.

  • xg15 2 years ago

    I know you should wash lettuce before eating, but that seems like overkill...

    (jk)

jsnell 2 years ago

(2021)

https://news.ycombinator.com/item?id=26201160

squarefoot 2 years ago

No idea if others at Twitter suggested this as I can't read the thread (and have no intention to subscribe) but a nice add on would be a score inversely proportional to the travel an iceberg would need to obtain a stable floating position, with ideally the very hard goal to draw it already in a perfect stable way, waterline height included.

  • Someone 2 years ago

    It isn’t too hard to get fairly close to that by drawing something that’s extremely stable, for example something very wide but not tall or an equilateral triangle, with one corner facing down.

    Then, use your first attempt to correct for the correct height.

    ⇒ I think a good game would need some other constraint, maybe score more for max height above the surface, or for how long a polar bear can keep their feet dry while it melts (a very wide but not tall stripe will melt faster than something resembling a ball)

arun-mani-j 2 years ago

Very cool (literally) stuff. I drew a straight line and it keeps spinning :D

miduil 2 years ago

Kinda funny to draw the classic examples of "tip of the iceberg" to see them ending up flipping :D

praptak 2 years ago

The center of displacement is always below the center of mass, so the iceberg never gets the stability of a rock hanging on a thread (ships can do that with ballast).

The only way for an iceberg to achieve stability is "differential" - every infinitesimal movement needs to move the center of displacement in a way which counters the movement. This basically means flat bottom.

kazinator 2 years ago

https://i.imgur.com/z7mQVWq.png

https://i.imgur.com/YLPYITL.png

https://i.imgur.com/Q7T0zns.png

tedunangst 2 years ago

Not so easy to get just the tip of the iceberg to stand out.

  • o11c 2 years ago

    Try drawing a "^" shape. The fundamental constraint is that the iceberg hates going too deep; with the two legs, any rotation would force that and is thus forbidden.

    A flat bottom can almost work but is highly prone to accidental asymmetry.

  • navane 2 years ago

    A very flat triangle with convex flanks does the job

  • ant6n 2 years ago

    Draw a fat boat with a very thin long mast.

mrcwinn 2 years ago

I’m so over flappy birds now.

kromokromo 2 years ago

To the author: Would be interesting to store all the shapes people are creating and let us quickly browse through them.

Mostly penises most likely (like any "draw something online" service).

(I am also guilty)

  • joshdata 2 years ago

    Yeah, I don't want to be responsible for user-generated content, and I don't want to collect data on users.

mhatma 2 years ago

This is very entertaining.

taneq 2 years ago

From my brief experimentation I have determined that the precise initial orientation of the dick^H^H^H^Hiceberg is critical to its final orientation.

amelius 2 years ago

How do we know there is only 1 stable position?

(A perfect circle would have many, but you could consider that a degenerate configuration.)

  • eternauta3k 2 years ago

    There isn't necessarily just one. A rectangle-ish form could have 4.

    • amelius 2 years ago

      Yes, rectangle would also be degenerate. Basically any configuration where adding an epsilon weight somewhere generates a non-epsilon shift so to speak.

      • eternauta3k 2 years ago

        To me, "degenerate" means that it has a symmetry so that the different states are somehow identical (e.g. equal energy in a quantum system). If it's rectangle-ish (say, an imperfect hand-drawn rectangle) then it has 4 distinct equilibrium positions. Not sure if we're thinking of the same with "degenerate".

      • s1artibartfast 2 years ago

        A plus shape "+" has four stable equilibriums which all stable optimums, resistant to weight and self correcting.

      • marcosdumay 2 years ago

        You mean unstable?

ljsocal 2 years ago

It would be interesting to create a version of this that would show how different displacement hull shapes would float.

blackoil 2 years ago

For me multiple humps seems to be most stable

nick7376182 2 years ago

Would be cool if it melts preferentially, choosing either air or water to be "warmer".

talkingtab 2 years ago

My fun was to try to get the widest underwater part with the narrowest top showing above.

alphanumeric0 2 years ago

This reminds me of gömböc

Gunax 2 years ago

Very cool, simple, and easy. This is exactly what demos should be.

Obscurity4340 2 years ago

This would make a great "fidget" app

personalityson 2 years ago

Bug? https://i.imgur.com/VraUTnq.png

amelius 2 years ago

Now let a polar bear walk on it.

barfbagginus 2 years ago

Note that many icebergs have more than one equilibrium, with various final heights above the water.

For example this iceberg towers above the water in one equilibrium, but barely rises above the water in its other equilibrium.

https://ibb.co/SdcKMBV

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