wilson@b11.ingr.com (Jon Wilson) (07/16/90)
From: wilson@b11.ingr.com (Jon Wilson) POWDERED aluminum burns most impressively. Mixed with iron oxide (oxides of any of the ferrous-group metals, like chromium, will work as well) it's known as thermite. Thermite is an interesting substance. Half-and-half powdered aluminum and iron oxide (rust), ignited by a bit of magnesium ribbon, makes for a rather spectacular lab experiment. Put a tray of sand under the (expendable) crucible containing this, and you will get a small, white-hot nugget of very pure iron. It will melt the bottom out of the crucible, though, and just about anything else. Thermite is a major ingredient of incendiary bombs. Jonathan "Don't try this at home, we're trained professionals" Wilson Intergraph Corporation
henry@zoo.toronto.edu (Henry Spencer) (07/19/90)
From: henry@zoo.toronto.edu (Henry Spencer) >From: wilson@b11.ingr.com (Jon Wilson) >Thermite is an interesting substance. Half-and-half powdered aluminum and >iron oxide (rust), ignited by a bit of magnesium ribbon, makes for a rather >spectacular lab experiment... If you're satisfied with only a transient ignition, there's a simpler way. Take a metal bar. Wrap aluminum foil around one end. Pick it up by the other end, and strike a hard glancing blow against a rusty surface. You get a small bang and flash as a thermite reaction ignites for an instant at the point of impact. Do not try this in an inflammable atmosphere! For a while, there was a belief that mines with flammable-gas problems should use light-alloy tools to avoid striking sparks. Accidental explosions were reduced considerably when this little demonstration convinced them to switch back to steel tools. Henry Spencer at U of Toronto Zoology henry@zoo.toronto.edu utzoo!henry