By taking a water soluble material, such as sugar resin, and making it into an egg shape then creating a vacuum within and sealing the egg to preserve the vacuum one will have a vacuum egg.
The vacuum created will cause the egg to implode due to outside air pressure. A vaccum will not sink in water or other various liquids but instead will float. So that the vacuum egg will disolve before the drinker notices the sugar resin must be highly water soluble.
So the sugar resin must be strong enough to contain the vacuum and heavy enough to make it sink. If the egg remains whole, place it in a cup then pour a beverage, say coffee, in. The liquid being opaque is key so no one will notice the vacuum egg. When the sugar has disolved enough the vacuum will suck in a great deal of the coffee leaving the person with less drink then they thought they had.-- MrDaliLlama, Oct 29 2004 Ask A Scientist: Vacuum Buoyancy http://www.newton.d.../phy00/phy00844.htmResult 1 of 17,800 for (a google search) for the words vaccum and buoyancy together. I'm afraid the poster was pulling our collective legs. [jutta, Oct 29 2004] But would an evacuated egg sink?-- bristolz, Oct 29 2004 Exactly what I am wondering, but in a search of the internet I cannot find the topics "buoyancy" and "vacuum" together.-- MrDaliLlama, Oct 29 2004 If high school physics still serves me adequately, a vacuum would actually be more buoyant than air.-- nick_n_uit, Oct 29 2004 Well, you'll find it from now on.
Suggest you place your head in the sink and see if it floats. My prediction is that it will bob like a cork.-- ConsulFlaminicus, Oct 29 2004 What is the point of this suggestion? An overly-complicated, difficult-to-manufacture, fragile and prohibitively expensive.....sugar cube? Sorry, but this idea doesn't float.-- vigilante, Oct 29 2004 A vacuum will weigh less than the liquid it displaces, so will float (Archimedes described this more than 2000 years ago). Unless you can identify a suitable soluble sugar with the strength to contain an egg-sized vacuum, and the density to make it sink, then this idea should be [marked–for–deletion] bad science, magic.-- suctionpad, Oct 29 2004 "what is the point ...?" to make a mess in the kitchen of course. Boys....-- dentworth, Oct 29 2004 Its not like you'd have to drill a hole and suck the air out, you could have a heated egg shaped mold with a small amount of liquid sugar in it spinning in a multi-directional centrifuge as it cools. Wouldn't the fact that it's egg shaped make for a strong enough container to not collapse while holding in a partial vacuum?Now if I can just figure out how to suspend a peanut in there...-- 2 fries shy of a happy meal, Oct 29 2004 Now that i know vacuums are less heavy than water I know this would not work by the vacuum alone. Thanks to (jutta) for that link and (suctionpad) for the idea to make the sugar resin used more heavy enough to sink. I will adjust the idea to reflect this.-- MrDaliLlama, Oct 29 2004 Vacuums are lighter than the air they displace? Tell that to my Hoover, it's heavy as a brick. Joking aside, this sinking egg idea just doesn't float. Well, OK, it does. That's the problem. Look up the ideas for "vacuum spheres" here. Many people, including myself, have done the math to see what sort of forces are created when dealing with vacuum vessels. Sugar just ain't gonna cut it, nor is anything else that you'd be able to hide in a glass.-- Freefall, Oct 29 2004 Seeing the reaction of someone whose sugar cubes briefly float on top of their tea might be fun, though.-- jutta, Oct 29 2004 Strange. I don't know what numbers everyone else is using, but mine work out fine. Well, as long as you start out with a very thick egg and a very small vacuum bubble. Or you could switch from the egg model to a paper cup with a false sugar bottom.
Oh, and I'm with [oniony] about the idea. Highly expensive way of cheating people out of a cheap yet high-profit item. Not going to bun it though.
[jutta] Yes. That idea I would have bunned.-- Worldgineer, Oct 29 2004 So we'd be getting more volume reduction simply through displacement, but not much from the actual vacuum. Seems like you'd be just as well off dropping in a big lump of sugar, without all the added trouble of making an airtight shell.-- Freefall, Oct 29 2004 Of course you would. And much better off skipping the whole proceedure. But I don't think that's the point. Though I don't really know the point.-- Worldgineer, Oct 29 2004 Really any gas would do the same thing, except bubbles would be visible briefly. With hot beverages, I think the egg would dissolve very quickly. Perhaps even before the cup was filled. This would mask the bubbles.-- swamilad, Oct 31 2004 Heh. And the point, even further.-- Worldgineer, Oct 31 2004 The purpose here (as I understand it: to confuse or trick a drinker) doesn't especially require a vacuum: a conventionally hollow shell would work just as well, although it would leave air bubbles.
But many trick glasses/mugs already exist, which divert the drink into a false bottom or completely contain the drink inside the clear hollow walls.
My own personal favorite for serving the victim less than they thought they were getting are the trick mugs with frogs in the bottom.-- DrCurry, Oct 31 2004 random, halfbakery