My science teacher gave us a tank of liquid nitrogen in high school and left us to our own devices. A rose is pretty cool to smash, so are are tennis balls. It also makes Dippin Dots.
Tried to rep but it's too long: All of the fun liquid nitrogen experiments involve blowing up sealed containers. The only problem with doing that is it's really unpredictable - modern plastic bottles are extremely strong and you can't really tell when they're actually going to burst, but anything that's predictable won't make a satisfying boom. The bottle is going to sound like a gunshot when it goes off, so if you have combat vets at the party, don't be surprised when they hit the ground. The ice cream is cool but it melts really fast so eat it quickly or put it in the freezer. You can shatter newer pennies since they're mostly zinc. Freeze one and hit it with a rock/brick/hammer. Doesn't work with older, real copper pennies. Just about anything rubber also shatters pretty nicely. Pretty much anything (especially edible) that you can freeze and then shatter is entertaining. Bananas freeze super hard and basically turn into rocks, but citrus can be shattered.
Hi! It's been a long time since I posted, but I had a question that I felt could easily be answered here (I hope.) Someone on another forum posted a well established mathematical "Proof." After a little bit of work, I completely disproved it. And I disproved it 5 different ways. The question is, who do I talk to get this vetted and accepted? I'm an engineer / gunsmith (albeit a spectacularly smart one), but I know nothing about the world of Academic Mathematics.
The world of mathematical publishing can be pretty opaque if you haven't any contacts. You can always try to send your proof in to some of the reputable (or less reputable, I guess) journals, but do realize that they will charge you a peer-reviewing fee (so it might be a good idea to be pretty confident that you haven't any serious holes in your argument). The following is an open-access alternative, run by some exceptionally reputable mathematicians: <a class="postlink" href="http://journals.cambridge.org/action/displaySpecialPage?pageId=3896" onclick="window.open(this.href);return false;">http://journals.cambridge.org/action/di ... ageId=3896</a> This being said, I would really recommend that you type up your several proofs (the math community prefers LaTeX), register for an arxiv.org account, and post your work there. This will establish priority, and then you can send your proof around and ask for the input of the relevant experts/the math community at large to vet your work (math.stackexchange would be a very good place for this). Without knowing the field of math to which your proof pertains, or the nature of the result, it's hard to give more specific advice than the above. Do keep in mind, however, that proofs in mathematics are subject to an exceptionally high degree of scrutiny, and so I find it unlikely that a "well-established proof" turned out to be erroneous, but it's not unheard of. I would just recommend you make sure your proof is water-tight.
<a class="postlink" href="http://gizmodo.com/5990383/the-future-of-nuclear-power-runs-on-the-waste-of-our-nuclear-past" onclick="window.open(this.href);return false;">http://gizmodo.com/5990383/the-future-o ... clear-past</a> Are we all saved? This is obviously a very simplified viewpoint, but...well, HOW simplified? What are they overlooking in terms of risks?
From what I gather: The technology is there for actual reaction, and has been since the 50s (according to the article), but where they are having problems, and rightly so, is the containment of the liquid salts. It turns out that the salts like to eat anything and everything (like your mother). It has been exceedingly expensive to create containment systems to store the liquid salts. There has been some hope with nickle super alloys and heat / chemical resistant ceramic linings, but even these are eaten away over time. The Europeans are making large strides in this, since it is not seen to be cost effective for North American companies to do the research. Biggest draw for this technology is the low waste generation, the billions of tons of thorium salts that we have available (very common by-product of mining) and how safe it is. Remove the fuel and it stops reacting, system solidifies and problem is taken care off. TL;DR, awesome idea, fundamentally sound, too expensive to operate due to materials issues.