[Before we go any further, I would like to make it clear that what we are talking about here is something that *looks* like a nuclear explosion, not something that will knock out the hifi, nuke the goldfish and give Granny radiation sickness. Moreover, we do not condone nuclear weapons, nor their use for entertainment, in any way whatsoever.]
Lava lamps rely on convection to generate the shapes of the blobs as they rise and fall. Likewise, the distinctive shape of the atomic fireball comes about from convective effects - indeed, you can get similar looking, but rather smaller, fireballs from gasoline explosions.
So, we will experiment with the "lava" material and the liquid it floats in (washing-up detergent, if the last one we broke was anything to go by), until we get a lamp that, once it reaches the critical temperature, erupts with an incandescent fireball, roiling nuclear style as it forms its mushroom cloud. Then it will settle down again until the cycle repeats.-- DrCurry, Dec 28 2003 The perfect lava substitute http://shop.store.y...cery/lylgolsyr.html... and also lovely on ice cream [jonthegeologist, Oct 04 2004, last modified Oct 21 2004] Lava lamp ingredients. http://www.oozinggoo.com/ll-form5.htmlAsk your local drycleaner for something called Perchloroethylene. [2 fries shy of a happy meal, Oct 04 2004, last modified Oct 21 2004] [DrCurry] I have the material you need.
At the University of Bristol (UK), years of work finally concluded that the best lava substitute for experimenting is Tate's Golden Syrup [linky]. When cool, it flows just like pahoehoe lava. When heated, its viscosity changes in line with lava. It splutters, bubble and spits like lava.
Just can't quite figure how to get the cloud effect, but everything else is there. Damn you [DrC], you beat me too this idea!
<aside> there are two generic types of lava, both named after Hawaiian phenomena. aa (pronounced a-ha) lava is angular and blocky and doesn't flow that fast. Pahoehoe (pronounced pa-hoe-ee-hoe-ee) is smooth, ropey and can outrun a gazelle. </aside>-- jonthegeologist, Dec 28 2003 I love this idea Dr.C and think I may have a way you could make it work. If you can find an oil or wax that is less dense than jonthegeologists' corn syrup but more dense than the rest of the liquid in your lamp, you might be able to get your mushroom cloud effect by very quickly heating the bottom of your lamp while it is cold. The heat will build up in your base liquid for far longer than it would normally take to begin to rise because it will be trapped by the medium density wax until it has transferred enough heat to be able to break through it. At this point some of your middle layer will be hot enough to rise with the bottom material and if it was colored differently, ( say bottom-yellow, middle-orange), the orange should be dragged to the surface in small blobs that will be thrown off and descend more quickly than the yellow like sparks or ejecta. I think the mushroom will form on its own because of how quickly the corn syrup will want to rise. If the heating element switched off as soon as the syrup brakes through then the three liquids should re-separate into their respective layers. (+)-- 2 fries shy of a happy meal, Dec 28 2003 Isn’t a mushroom cloud just a blob of dusty hot air rapidly rising? Perhaps some cloud formation thrown in as well? Not the combination of two fluids like in a lava lamp?
To simulate this on your desktop, I propose the following half baked idea:
What’s needed: A particulate (slightly heavier than the working fluid) to show the motion of the column of heated fluid, a working fluid, and a source of rapid heating.
How to build: Fill a large jar (fish tank or whatever) with a somewhat viscous fluid, like transparent mineral oil. Add to this fluid some small, very small, particles that provide a great deal of contrast, but settle to the bottom to form a nice even layer. I’m guessing some sort of tiny plastic beads of the correct density would do it. Next, install a very high power heat source to bottom of the reservoir – only covering a small circular spot, right in the middle. It has to be able to provide a (relatively) great deal of heat for a brief period of time.
Attach the heater timer to a flash strobe (located on, or near, the heater), and a 20Hz sound generator, so that when the heater “goes off”, there is a blinding flash and a low frequency noise to accompany it. After your eyes have readjusted to the ambient light level, you should witness a blob of hot mineral oil rising from the bottom of the tank, dragging up all the contrast beads with it, and if designed correctly, forming a nice mushroom cloud.
As the cloud cools and dissipates, you could enjoy watching the beads return to their resting position in a beautiful display of “fallout”.-- TIB, Dec 29 2003 random, halfbakery