Gum arabic alters the surface tension of water, reducing the solubility of substances within it. Some, like salts and sugars, precipitate out and down. Some, like gases, precipitate out and up.
Pullulan is a mostly-odorless mostly-tastless polymer that comes from yeast and is the basic backbone of soluble breath strips, like those from Listerine (link).
For those wanting to prank their friends something good, this would be a blank 2-liter bottle screwtop (which I think should also fit one-liter and 20-oz bottles) manufactured to fit a specific brand - Coke and Pepsi lids, as far as I know, aren't interchangable.
Hidden in the top of the lid would be a small piece of gum arabic, held in place by a thick sheet of pullulan.
When you're sure nobody is looking, you would simply screw this onto your friend's soda bottle, maybe in the fridge (or at a party, any old bottle on the counter). The soda would release moisture which would contact the pullulan sheet, eventually causing it to break down. This might take a few minutes, or it might take days.
This drops the gum arabic into the soda, and thus releases the carbon dioxide stored therein. With the lid screwed on tight, the gas has nowhere to go, and would create a high-pressure region in the soda container. If this doesn't blow up the container, it certainly will cause a huge mess the next time it's opened.
This would be sold in an airtight (perhaps with an argon atmosphere) container and a pull-off cover. Available in several common colors, like black, red, white, and blue.
Inspired by [2 fries]'s "Delayed Mentos" idea. Feel free to holler redundancy.
(Side note: I love the "ha-ha dangerous" subcategory)-- shapu, Feb 16 2006 Delayed Mentos Delayed_20MentosInspiration. [shapu, Feb 16 2006] Pullulan http://www.answers....gwp=8&curtab=2222_1 [shapu, Feb 16 2006] This is quite a fun idea. I wonder if the moisture would be enough to break the Pullulan, if it is the same stuff found in breath mint strips. They instantly dissolve on your tongue, but I don't know about the limited moisture coming off the liquid.
However, if this was shaken the Pullulan would instantly dissolve and the bottle would explode violently, thoroughly scaring the shaker.
Bun for creativity.-- dbmag9, Feb 16 2006 The delay is part of the fun, I think. I'll modify the idea a bit to get at that.-- shapu, Feb 16 2006 db, have you done your homework yet?-- po, Feb 16 2006 Instead of pullulan, use a simple mechanical device. It should be easy to create a container inside the lid that is opened when you twist the lid off (but doesn't open when you twist the lid on). That way there will definately be someone there to experience the fun.-- Worldgineer, Feb 16 2006 + When I worked for a Coca cola distributor we would have to install the restaurant pre-mix machines and I learned that the amount of carbonation is adjustable. It got me to wondering if a guy could build a multi-staged carbonated water rocket that would release the gum arabic in each new stage as the previous one dropped away.It was a toss up between posting Delayed Mentos and that.-- 2 fries shy of a happy meal, Feb 16 2006 [2fsoahm]: I'm sure you could do both.
[World]: The easiest way to do that would probably just be to have the sheet of whatever extend all the way across the threads, rather than (as I envision this particular product, anyway) ending before it would be cut up by the bottle top itself. I hope that makes sense.-- shapu, Feb 16 2006 No I haven't [po], and it's all because of the HB! Damn this irresistable place of happiness! But how did you know?-- dbmag9, Feb 16 2006 She probably hasn't finished hers either.
[shap] I was thinking of something more complex*, but that sounds like a very simple and easy solution.
*Specifically, a piece hinged in the center that would contact the walls of the bottle and restricted by a peg from turning in one direction. When turned the other, holes would line up and release the gum. Think of a cheap closable salt shaker.-- Worldgineer, Feb 16 2006 Redundancy! Redundancy!
There. Are you happy now?
[+]-- DesertFox, Feb 16 2006 Drop in a few chunks of dry ice and screw the top on before it melts. I've blown up many a soda bottle with dry ice, and can attest that the delay is part of the fun.
It may take some practice to get the amount right, in a bottle with soda in it. The carbon dioxide may dissolve into the liquid if there is a long delay--which could be interesting.-- baconbrain, Feb 19 2006 random, halfbakery