Thermite

[foolish01]

on brainiac they test thermite (iron oxide, and aluminium or summat), but surely if a more rective substance was used instead of aluminum (Lithium /Soduim for instance) it would be way cooler and explosive

[jake-the-peg]

Lithium and Sodium are not good because they both occupy the same column on the periodic table - They both react in the same way. Note Oxygen is way over on the other side so they both react violently with the oxygen in water.

Aluminium is actually very reactive. but you don't normally see it the moment it's exposed to air it forms an immediate protective layer of aluminium oxide which is what you see and why aluminium isn't shiny.

However it can be made to react and very violently as you saw on the program. I think the Space shuttles main booster engines use a similar reaction.

[foolish01]

ty but i meant iron and sodium coz there beta

fool

[Gef]

It's all to do with enthalpy changes. The enthalpy of formation of aluminium oxide is far greater that that of sodium oxide or lithium oxide and so the reaction with aluminium oxide produces far more energy.

[bigveg]

as thermite is used mainly in the steel industry for cutting through ingots and bars etc, it would be too dangerous to have metals like sodium or lithium. they have to be kept under oil because if they come into contact with water, the metal ions bind with the oxygen to make an oxide, releasing hydrogen. this reaction is somewhat violent and tends to ignite the released hydrogen so the poor ****** trying to cut the steel may get blown up (or at least soil his pants and get burned). also aluminium is used because it requires a high temperature to ignite it (you cant light thermite with a lighter, i have tried... but you can with a burning strip of magnesium) and also gives out a shed load of heat. the iron oxide, or rust, donates its oxygen particles which allows the aluminium to burn. ps dont put thermite on a car bonnet and light it if you can avoid it.