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Help wanted! Constructing model volcanoes


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I haven't really built one but i need help making one, i am posting different threads in different categories hoping that someone might help me if they see the thread...


I have been given an assignment in regard to constructing a volcano model for my earth and space science class. I have browsed through your site, I must say it is helpful, but I can't find a volcano that would be for a high school student; I was wondering if you have any information about how to make a volcano for my class, I am in grade 12. What I am looking for is some way to control the model volcano, like before it erupts it shakes (if it has to take chemicals to do this it is fine), volcanic ash spewing out, someway I could control its viscosity, a chunk of the upper half of it collapsing, pyroclastic material flowing out, lahars, I heard volcanoes shift to one side before exploding if that it possible to perform I don't mind using different material in constructing the volcano. I know these are a lot of requirements, but I would be grateful if you could help me, or if not guide me in the right direction, with links etcetera.


Thank you for your time

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You ask quite a lot from the volcano model. There are a few chemical volcanos. One is based on ammonium dichromate, giving real fire, but the smoke is not real, it produces ashes of chromium (III) oxide. The volcano effect is due to the large expansion of volume.

Another volcano is based on a viscous liquid, filled with sodium bicarbonate, and adding an acid to this. The foam strongly expands, giving rise to eruptions, if constructed well, but of course, no smoke, heat, let alone pyroclastic clouds etc.


Another idea might be to use a computer model for volcanoes. I can imagine that such models exist, and otherwise you could try to make one from general models on fluid flows, gas flows, etc. The latter approach probably is not the easiest though if you lack the physcis and math knowledge.

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a Motor with an off-center weight will give you shaking effect.

expanded polystyrene will dissolve in the presence of petrol type solvents so a silicon tube with little holes threaded throughout this and a solvent injected into the tube will make it cave in as if molten.

you Could as Woelen suggests use a bicarb/acid mix to foam up, Or make a pre-made viscous liquid and use an expanding bladder at the base to push this out (like blowing up a whoopie cushion) this will displace the liquids nicely and not have a foam type look to it.



failing that, fill the thing with Ammonium Dichromate and light the Top :)

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  • 3 weeks later...

The person, who wrote the webpage probably did not know very much about chemistry. Dichromium sulfate does not exist. But, given his description (orange powder), I'm almost 100% sure that he means ammonium dichromate. Ammonium dichromate is an orange powder, which easily is ignited. Mixing this with sulphur will make the 'lava' more realistic. Ammonium dichromate on its own will result in formation of a very fluffy green and very voluminous powder, while it is 'burning'. The mix with sulphur will yield a dark colored more lava-like substance, when it is 'burning'.


Be careful with ammonium dichromate though. It is a carcinogen. The volcano-experiment used to be quite popular, because it makes a fairly safe, yet spectacular, demonstraton. Besides that, ammonium dichromate is a nice and interesting chemical, which seemed not to be dangerous (e.g. it is not explosive, extremely corrosive, or otherwise immediately dangerous). But unfortunately, it is a carcinogen, and since that is known, the use of this funny chemical has diminished quite a lot.

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  • 4 months later...

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