… and then the Dean was like, “You’re done.”
Ugh, unfortunate mix of numbers. The bullet is doing 922m/s, the balloon is doing 93m/s.
I lived on the third floor in Tercero at UC Davis in 1976, We rigged up a 2x4 slingshot on the balcony of the third floor and tossed water balloons the better part of a city block. We knocked the sliding glass door of the building across the way, but didn’t break it.
I tossed a water balloon at the trams visiting the dorms on Picnic day. It ll hit some poor woman in the side of the head and I saw the recoil. Christ, I felt awful as I had never really thought about the mass of hardball sized water balloon.
The port-a-potti incident was not only an over-sized “balloon”, it was not a balloon in the sense of the toy balloon kids know - notice it stayed spherical, whereas a toy balloon would have flopped and deformed.
I suspect this would be a strength-of-materials issue as much as it is a kinetic energy issue. A toy balloon will burst if handled incorrectly - which is a huge benefit for the target.
Putting a liter of water in a cannon ball vs cling wrap, as it were - the issue is how soon the weight is going to run off the skull (let’s assume you can hit your target) - is it going to stay long enough to deliver 100% of its energy down the spine, or will it feel like a quick slap while providing an sloppy shower?
I’m leading toward the latter.
Not true. The older kevlar helmets were able to stop bullets from some angles.
MIT circa 1975.
These scenarios are all assuming that your target isn’t the Wicked Witch of the West. If it is, lethal distance is much, much shorter.
Not to mention the Triffids (1963 movie version only), the ant-like aliens in Jack Chalker’s Well of Souls series, and Tim Benzedrino.
It’s sort of like getting hit by a paintball, right? I bet getting hit by a water balloon moving as fast as a paintball would cause injury.
Or the aliens from Signs.
You’d probably need a really big balloon for the Sandworms on Arrakis.
…and then step back to avoid being drowned in the Water of Life. Whether you’re worthy or not.
That’s a good comparison. The muzzle velocity of a paintball is ~90 m/s. A paintball at point blank range will often raise a welt and may break the skin.
A water balloon probably has 50-100 times the mass of a paintball, and would do some serious damage at that speed. It certainly could break a bone or even kill someone if it hit them in the head.
But a paintball is far more rigid and has a smaller contact area. You can’t just extrapolate from that.
If you hit them right over the heart immediately after the left ventricle contracts but before it has time to relax, it takes very little force.
Which does remind me, back in my student days, the surgical rubber water bomb launchers were used on our equivalent of rag day. One year a woman was hit in the chest by one and had a significant cardiac episode. She didn’t die, but it wasn’t good. I think this subsequently caused the banning of these overgrown slingshots.
Another data point.
When I was an undergrad they had “Warrior day” at college where we all fucked off for the day.
Several of us got together about 60 feet of surgical rubber tubing and a dog food dish. Drilled some holes in the dish and strung three ten foot rubbers on each side. Had two guy hold the rubbers and one guy to walk backwards 20-30 feet, hold the dish just right and let fly. Some of the balloons broke on launch, but most didn’t. We had fights with several other teams, but due to our superior firepower (3 rubbers instead of two) and our superior balloon holder we could out range the other teams, we were shooting well over 100 yards.
Anyway in the afternoon, they staged a raft race in the reflecting pond, about the size of a football field. We were set up on one side of the pond shooting at teams on the other side. Due to the short range, we were letting fly pretty much horizontally. We were shooting over the heads of the seated raft paddlers.
Anyway I pulled back about 20 feet and let fly at our rivals on the other side. Right as I let go, a guy in a raft right next to our side of the pool stood up directly in front my speeding water balloon. He took it right on the side of the face. He was maybe 10 feet from the point the balloon left the dish. The balloon did not break, but it cleaned that guy right off the raft. 
Didn’t kill him, but he had one hell of a bruise.
Are you saying smaller water balloons do more damage?
Rag day?
I had no idea what that was either. Apparently it’s related to this: