Hi,
A colleague of mine is helping her daughter find information for making a volcano as part of an ecosystem science project. My colleague is looking for ideas to make an erupting volcano with a more realistic lava than just baking soda and vinegar. I figured if any group could come up with some good ideas, it would be the straightdopers.
So how about it … what would you use to make a homemade volcano erupt and produce lava like stuff.
The problem is you can’t get it to spew anything for a significant period of time unless you had a huge tank of something hidden under the table. I think painting it very realisticly and putting dry ice in alcohold or antifreeze would give a cool smoke effect for quite awhile.
First of all, thank you for not just doing yet another baking soda and vinegar volcano! They always win school prizes, but they demonstrate absolutely no science whatsoever.
As for the lava, you want something thick and viscous, so as to flow slowly. Corn syrup with food coloring might work well, but you’d need some sort of pumplike mechanism to make it “erupt”. It’d probably also be nice if you had something which could harden in place, but I’m not sure how you could do that. You could use melted wax, I suppose, but the school probably prohibits heat sources in science projects.
By the way, if you go with dry ice smoke, alcohol or antifreeze isn’t necessary. Water will work just fine, and will be a lot easier to get school approval for.
Screw the science. The BEST volcanoes are done using sodium bichromate (at least I think it was sodium; maybe potassium). It’s an orange crystaline powder that, when ignited with an ordinary match, shoots way-cool yellow sparks skyward. The process turns the powder into dark green ash that rains down on the miniature landscape in a 1’ - 2’ radius around the crater. Makes for kick-ass faux lava and ash effect. Add a few matchheads to the mixture to get flying, flaming “rocks.”
Trust me, this voclcano will be the hit of the fair.
(I love science, so don’t take my “screw the science” crack seriously. Grinny.)
A mixture of sulphur and iron filings will bubble and steam when water is added (takes a couple of minutes to get going.) The heat evolved is fairly significant, so the easiest and safest construction is dry soil piled into a cone over your mixture, and tip the water into the top.
Waaaay back in grade 5 my buddy did a “volcano” project.
He made up a thick orange substance (maybe some type of batter with orange food colouring). He then powered the volcano with a foot bellows pump (the kind you use to inflate a rubber raft).
It was pretty cool.
MtM
:dubious: Chemistry is not science?
You are right that they’re overused, and nobody usually stops to think about why it’s bubbling and foaming, but I’m almost offended 
If you go with the dry ice, acetone works well too (nail polish remover).
Here is a link to that dichromate volcano stuyguy mentioned, but please note the warnings. Lots of stuff ya dont’ wanna breathe.
Also, here are some links to more cool things to do with kids and chemicals… no, it doesn’t involve blowing them up
Have you considered having Chronos show up as a guest speaker after a late night on the town? I am sure that with the proper breakfast, his projectile vomiting would win a shiny blue ribbon.
Ammonium dichromate! That’s the ticket.
Thanks kunoichi.
You want your volanco as part of an ecosystem?! Umm, pyroclastic flow verses deer…
In the abstance of a chemistry store, you could try to use an aquarium pump to bubble corn syrup, red glitter and food coluring out of it. Or you could improvise with a strong plastic bag you squeeze by hand.
Of course, it’s not a true volcanic eruption unless there’s lots of fire and everything in 100km gets covered in ash.
According to my colleague at work, her daughter has to make an ecosystem that shows the nitrogen cycle … so the volcano is the part of the system that produces the nitrogen. I believe they also have included a goldfish and grass (the stuff on your lawn, not the stuff you smoke 
).