My opinion is to use your own property as a target, and not shoot at the local water tower. We don't condone that sort of thing here.

We *were* linked to in Tuesday's xkcd 'What If?' article, so I'm guessing that's why.

http://what-if.xkcd.com/

I found JSR's long-lost American cousin...

[youtube][/youtube]

@PVC, I had the same idea... Like what's used in wind tunnels. It might be quite restrictive, however.

Yeah, it must be something to do with the fact that the speed of sound in air DOES change somewhat with pressure. In an ideal gas, at least, this sort of effect would appear to be impossible. I'd love to do a course on fluid mechanics someday, it's fascinating.

So that's a PCP gun then? I see. Wikipedia still says that the limiting factor in a firearm is the speed of sound in the working gas.

I'm not doubting the video, just wondering why the limiting speed is above the SOS in the gas. No doubt there's some interesting physics going on.

Very nice! It's great to see a new idea being properly explored on the site. I've experimented with vortex cannons before, but only the little ones made of a bucket and a membrane. Nothing that can do more than ruffle someone's hair. About the supersonic flow... I'm definitely uneducated when it com...

Those pics look really washed out... Do you have something on the lens?

The S2 is capable of very vivid photos though. I still use a budget android, but my sister wanted a better phone for Christmas so I advised her to ask my parents for an SII. She's very happy with it.

True CS, but in that case I imagine pure hydrogen would be better. Oxygen is readily available from the air, along with a convenient buffer gas. Carrying just the hydrogen increases your energy density, and is far safer. The fact his buddy says it 'runs on water' is what led me to post my little the...

No offence, but your buddy is either lying, or mistaken. We've been through the whole 'hydroxy as a fuel' a few times on the forum. And these are the facts: 1: Water is not an energy source. You can NOT create a device which splits water using electrolysis, runs an engine with the gasses produced, a...

Jack, I dread the day when I'm stuck in the company of an overly proud parent of either gender. It sounds horrific. Perhaps I can continue your spudgun analogy, but twist it in my direction. I really love spudguns, but as biology would have it, only women can produce them, no exceptions. If I want o...

Snippity Snip Agreed on most points. There's still two that I don't agree with, however. (Damnit, being sucked into internet debate! :? ) I'll agree that there's likely a genetic reason why the average female would gravitate away from science/math/engineering. But this is only a generalisation... I...

Do you think that in a society of women the field of engineering would even exist? Without shoe-horning myself too deep into this debate... I imagine that in a society of women (suppose you could remove the need for a man to reproduce) you'd end up with a considerably different social atmosphere wh...

I know some people stop RC car engines by pushing a plastic stopper onto the exhaust. It doesn't look like it takes much to make them stop.

@Tech I guess it's difficult to make questions always be interpreted the same way... I took that question to mean 'humanity' inclusive of the workers and employees of said corporation, and inclusive of people who would benefit from the services of the corporation. I basically took the 'interests of ...