I think that may also be due to the different shape and construction of the rounds. Mass x velocity, absolutely, but pistol rounds tend to be big 'ole dumb slugs of lead with about the same aerodynamics as a brick. Centre-fire rifle rounds tend to be much pointier, even if they aren’t proper AP or SLAP. That makes the point-loading at the point of impact much higher, and the round holds together a bit longer before mushrooming out.
On the other topic - he could have done the same thing with big balls of frozen boiled water (boiled to get rid of the bubbles). Then all those shards just melt away.
See, that’s why humans need crystal balls. Focus ! Just to veer back and pile on Matt a little more; if they didn’t clean up that glass it could also present a fire risk with “focused” sunlight. I think he probably did clean up the mess anyway (or had someone do it…the views he gets must translate to lots of money).
People occasionally make frozen water balls where I live to line their sidewalks. They’ll put coloured water in balloons and set them outside to freeze. Throw a little sawdust in if they want them to be durable. Of course, in Texas that would not work so well
Ring of surface/sub-surface waves constructively interfering, well, destructively at the point of convergence is my guess too, but I could conceive of direct kinetic transmission through the glass having an impact as well - basically some energy punching through elastically and things going brittle near the boundary.
Pyecrete…Mythbusters made a boat out of it once…not altogether successful . They tried to make a hull, but the concept was artificial iceberg so they should have made a small barge
EDIT: just watched the Pykecrete video, had no idea it was that ambitious .
There is essentially zero chance that the round would bounce back (too much deformation of both the ball and the round) but when he fires the 50cal rifle, there is a piece of the ball that comes back and tries to bite him.
Unrelated to my earlier bad take about glass litter, would similar spalling still occur in (boiled) ice spheres? I’m just thinking about the crystal structure, bond energy etc and don’t know enough of the science here to have any intuition. I wanna say that ice is in a hexagonal lattice and quartz in a trigonal something-or-other but it’s been a while since materials science.
it would be different, for sure, and interesting in its own right. But would spaling occur … ? I think under the right circumstances absolutely yeah you could get ice to spall, but I feel that you would have trouble getting those circumstances to align using a sphere of ice and bullets.
When the house I grew up in was being built (around 1950), they found it was built on a Roman era burial. Presumably an entire graveyard, but no one’s ever checked.
The skeleton they dug up is in the Museum of Gloucester, but I don’t think it’s on display because they have plenty of other ones:
