Weird Science

Fireworks Ignited by Ice

Polish ver­sion is here

Is It Really Pos­si­ble?

The idea of star­ting a fire using ice seems, at the very least, bizarre. It’s hard to ima­gine any­thing less sui­ta­ble for igni­tion. In one of our pre­vious expe­ri­ments (ava­i­la­ble here), we alre­ady demon­stra­ted that water, if used cor­rec­tly, can lead to a vio­lent igni­tion. Below, I pre­sent a sli­gh­tly modi­fied ver­sion of that expe­ri­ment — one in which the igni­tion is trig­ge­red by ice.

Mate­rials Nee­ded

You’ll need the fol­lo­wing che­mi­cals:

War­ning: Always wear pro­tec­tive glo­ves and avoid skin con­tact with the rea­gents. While mixing the zinc pow­der with the other com­po­nents, all sub­stan­ces must be com­ple­tely dry! Do not grind the ingre­dients toge­ther — this may result in a dan­ge­rous explo­sion. Gen­tly mix the com­po­nents on a piece of card­bo­ard using a woo­den spa­tula. Do not store the mixture! Con­duct the expe­ri­ment under a fume hood or out­do­ors. The author accepts no respon­si­bi­lity for any damage or injury. You pro­ceed at your own risk!

Demon­stra­tion

On a piece of card­bo­ard, gen­tly mix 4 g (0.14 oz) of zinc pow­der, 0.4 g (0.014 oz) of barium nitrate, 1 g (0.035 oz) of ammo­nium chlo­ride, and 4 g (0.14 oz) of ammo­nium nitrate using a woo­den spa­tula. All com­po­nents must be per­fec­tly dry! Mix them slowly and care­fully — never grind them toge­ther! Shape the resul­ting mixture into a small mound on a fire­proof sur­face (cera­mic, asbe­stos, or metal):

Ilustracja

Then, place a piece of ice direc­tly on top of the mound. After a few seconds, the mixture igni­tes vio­len­tly, pro­du­cing a pale green flame:

Expla­na­tion

In dry form, the sub­stan­ces do not react with one ano­ther. Howe­ver, a micro­sco­pic layer of water on the sur­face of the ice is suf­fi­cient to ini­tiate a highly exo­ther­mic redox reac­tion between the zinc and ammo­nium nitrate. The reac­tion is fur­ther acce­le­ra­ted by the pre­sence of ammo­nium chlo­ride and barium nitrate. The green color of the flame is cau­sed by the barium salt.

Enjoy this explo­sive and edu­ca­tio­nal expe­ri­ment :)

Fur­ther rea­dings:

Marek Ples

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