Part of the criteria for my project was that my 'Grenade' had to be transportable, rather than the more traditional rockets which started the reaction by being inverted. I wanted mine to be able to be inverted, and even lightly shaken (not too hard though).
It is important to note that the person weilding a chainsaw-bayonet in my profile picture is not me!
Step 1: Step one - acquiring the materials
Some vinegar (enough to half fill 1 canister, but more if you intend to repeat)
Some baking Soda, ie bicarbonate of soda (again, enough to half fill 1 canister)
Some ordinary kitchen aluminium foil - about 2 square inches per grenade
Some tape - you will need something strong enough to make a decent seal, I used something resembling insulation tape from my dad's workshop
Something heavy and uneven - I used a steel nut
A pair of standard film canisters - I got mine from a photography centre down the road
Step 2: Step 2 - Building the Grenade
Step 3: Step 3 - Creating the 'cap'
Step 4: Step 4 - Sealing the two halves
Step 5: Using the Grenade
Finally you are ready to use your new grenade. Go somewhere that you will not upset your neighbours (like, for instance their front lawn. At 3 o'clock in the morning.) Then shake your grenade so that the seal is completely broken, not just ruptured. Then, once your are sure the reaction has started, throw it - quickly. I have had a few of these explode in my hand, and, contrary to popular belief, it isn't a pleasant experience. If you have built it correctly, the two halves should fly apart with a satisfying bang, rather scarily for someone nearby.
I hope that you have enjoyed making, and using, your grenade, and that you will make many more in the future.
<(-.-)> Cheezy Monkey
Please note: The video taken by my camera is not of a very good quality, and it does explode with a large bang.