AMAZING Indestructible Glass: Prince Rupert’s Drop vs. a Bullet at 150,000 Frames Per Second

That is a .22 caliber bullet shattering against a solid drop of glass.

What sort of object can shrug off a bullet, but shatters with just a little touch? The answer is a Prince Rupert’s Drop, an object formed from molten glass simply dropped into water to cool. I’ll explain how this works below, but first, check out the video below of Destin from Smarter Every Day shooting a Drop at 150,000 frames per second with a Ruger 10/22 rifle:

The Prince Rupert’s drop is a strange artifact that results from the way that a drop of molten glass cools in water. When the liquid glass hits the surface of the water, the outside material immediately begins to cool and harden into a solid, which creates the solid shape of the drop. However, because of this, the interior of the drop takes much longer to cool, and, confined by the already-solid shape of the drop, creates a tremendous amount of tension as the interior material shrinks and cools into a solid. This results in a bulb that has incredible inter-molecular forces and therefore great strength, but which exists in an unstable configuration. If even one link in the chain is broken, such as at the vulnerable tail end, the entire drop will explode into tiny pieces.

For more on Prince Rupert Drops, you can check out Destin’s earlier video on the subject, embedded below:

You can also see even more footage of Prince Rupert’s Drops from Smarter Every Day on his second channel:

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at


  • noamsaying

    Royal society curator should be wearing gloves to keep body oil off the pages.

    • Swarf

      It’s likely he came to the job with a fair bit of knowledge of what is and isn’t appropriate when it comes to the manuscripts he’s in charge of.

    • Edeco

      After years of being a scholar his oil and sweat glands have probably dried up completely.*

      Anyway, good stuff. Rupert/Rhine was a neat character; agile mind, unusually tall, military experience from a young age. Bizarre how he lost to guys twice his age who were mostly improvising.


    • Nicholas C

      One of my past jobs was working in a photo archive. I totally agree. He should be wearing gloves.

      • Jonathan Ferguson

        It’s the Royal Society Nicholas, he’s not an idiot.

        • Nicholas C

          I never implied that he was. However any serious preservation archive has rules to minimize tainting the collection with finger prints. Such as archival boxes and paper as well as acetate sleeves. And those are photos just from the civil war and recent.

          I imagine books from 1600 should be treated with the same mentality.

          • YerUncleWillie

            Except he knows more about it than you, and you should give him the benefit of the doubt.

    • SidViscous

      Watch Brady Haran’s “Objectivity” channel. This is the Youtuber that got Destin into the Royal society. They discuss that the Royal Society does not use gloves due to the fact that more damage is caused by ripping and the like because of gloved hands than from hand oils.

      Considering he is the Curator for the Royal Society I reckon he knows what he’s doing,

    • Old Vet

      I noticed that as well. I have noticed it a lot on other museum people also. Someone is not teaching preservation very well these days.

  • Sam


  • Swarf

    Well, that was pretty damn cool. Thanks for sharing it with us.

    • Dougscamo

      Yep….worthless….but cool….

      • carlcasino

        All Science is worthless until it turns into –say –Velcro?

  • Badwolf

    instead of shooting it with a bullet, make it into a bullet.

    • Edeco

      I hope Jeff Taofledermaus sees this. Want it to happen but not bad enough to make a youtube account.

      • SidViscous

        Well it would be a bit difficult to get the tail of the Prince Ruperts drop into the cartridge.

        • Badwolf

          I’ve seen PRDs with short tails. Those can fit.

          • William Elliott

            yes, but wouldn’t firing them shatter the tail, and therefor fracture the drop?
            Now my gears are turning…

          • Badwolf

            As I said… only way to know for sure is to test it

      • It’s funny, he was apparently planning to do this before Destin’s video even got released.

        • Edeco

          Awesome. Perhaps 50 years from now people with 2×1″ weeping scar tissue balls, or holes from removal of tissue balls, from being shot with weaponized PRDs will look back and curse this series of experiments/discussions.

    • Ben Loong

      A concern that comes to mind would be the shock of the propellant itself causing the glass to shatter as it’s being fired. Or the glass impacting the walls of the barrel and then shattering.

      • Badwolf

        Only way to know for sure is to test it.

        • VanDiemensLand


          • William Elliott

            damn, exactly what I was thinking…now how to make one without a tail in a good aerodynamic shape…

  • B-Sabre

    Anybody else notice that the shockwave is traveling up the glass faster than the bullet?

    Watching .22s splash against a glass bulb…amazing!

    • diana pierce

      this is exactly what happens when a jet plane penetrates the sound barrier. the air ahead becomes rippled and the advancing pounding jet continues forcing more and more air out wards. Sonic booms are wild to hear.

    • William Elliott

      The speed of sound in solids is faster than the speed of sound in air or liquids.
      sound travels at 343.2 m/s in air; it travels at 1,484 m/s in water (4.3 times as fast as in air); and at 5,120 m/s in iron.
      The official velocity of the “crack front” in a prince rupert’s drop is “1.45 to 1.9 km/s [0.9–1.2 mi/s”

  • Nicholas C

    Love his work.

  • abecido

    That is one rusty 10-22.

  • marine6680

    I really like his channel…

    It’s basically just a channel with an educated southern redneck having fun with what he has learned.

    So it’s right up my alley.

  • anon

    id be interested in seeing what caliber it would take to actually break it without the shockwave cheatey method

    • Swarf

      Broadhead arrow.

  • jay

    This technology was the base for Corning’s “Gorila Glass”, you see today on mostsmart phone screens.

    • William Elliott


  • uisconfruzed

    Fascinating combo of art, physics, wisdom of antiquity and great photography.

  • R Gabriel S

    Pretty Damned Cool ! Here’s a “Shot” at why… “Density Alignment”..? Extreme “flowing” heat into sudden extreme “standing” cold. Heat Rises (Lighter) / Cold Sinks (Heavier). i.e. Sudden/Forced molecular alignment. Heavier, Stronger “Face” of molecules… forced to “Cold”, Lighter, Weaker “Face”… forced to “Hot”. Gravity/Impact with water surface creates the “bulb”/sudden cold, heat “runs” away to “Tail”… (Water “closes back”, constantly directing the heat “Out”.) “BAM” Hard Head / Soft Ass… The very definition of “Balance”. Sound Good? Actually a very good “Demo” on how to make Stronger Projectiles. Mystery “Solved”??? :8-D