I discovered these fun little toys/weapons some years ago whilst playing “guns” with one of my friends, we would run around with plastic guns pretending to shoot each-other, having mock battles and trying to take possession of certain areas of the road we lived on. It so happened that we were taking these games fairly seriously and so decided that we needed a weapon similar to a grenade to play with, it was this which lead us to the “B-bomb” or “Bicarbonate Soda bomb.”

I must add that this was about eight years ago, we were nine/ten

B-bomb mk I

These bombs are safe, fun and cheap, they also involve eating chocolate and getting messy, I advise anyone too try making them at least once. To make one B-bomb mk I you will need:

One Kinder-Surprise Egg,
One teaspoon of bicarbonate soda (next to the baking powder in a supermarket),
One bottle cap of vinegar

This was the first version of the bomb and is fairly primitive. To put it together first eat the Kinder-Surprise Egg, marvelling at how they manage to get two kinds of chocolate into one egg, then open the capsule inside and put together the little toy, after breaking it half an hour later you are ready to make your bomb. Separate the capsule, into one half tip the vinegar, in the other half place the bicarbonate soda. KEEP THE TWO HALVES SEPARATE.

At this point carefully move the two halves of your bomb outside or into a pre-made testing areathe Nevada Desert would be ideal, but your back garden will suffice. With a quick flick of the wrist, jam the two halves together as hard as you can. You have about three seconds to do this. Drop the bomb and stand well back, in five to twenty seconds the two halves will fly apart in an impressive explosion of white foam.

Repeat until satisfied.

Now this was fine as a test, but my friend and myself needed a more practical version. Jamming the two halves together was tricky at best; if you got it wrong you spilt white foam or vinegar down you, we also needed to be able to carry a few of them without having to worry about spilling them, the two separate halves didn’t allow this in a battle situation, so the B-Bomb mk II was developed.

B-Bomb mk II

To build one you will need all of the above, and a spare plastic bottle top (the kind you unscrew).

This version is more complicated not much more, but pay close attention. Fill one half of the capsule with vinegar about ¾ up, (preferably use the larger half that fits inside the smaller half). Fill the bottle top with bicarbonate soda. Float the bottle cap in the vinegar. Close the capsule.

You now have a safety bomb, as long as it is this way up it will not go off. But turn it upside down and it’s armed which means you have between five and twenty seconds to get to cover. If you get it right you should be able to keep a few of these in a pocket padded with tissues, but accidents do happen. USE WITH CARE!

How it Works

The simple reason is it is a pressure bomb. Vinegar is an acid and bicarbonate soda is an alkali, when mixed the neutralise each other, but in doing so produce a large amount of carbon dioxide (CO2). This gas expands and mixes with the solution to produce the foam, the foam in turn expands increasing the pressure inside the capsule. When the pressure inside the capsule is greater than the pressure keeping it closed the capsule is forced open, creating the explosion.

Suggested Improvements and Innovations

  • Use lemon juice instead of vinegar, it smells nicer, Add a few drops of food colouring to the bicarbonate soda to make a colourful explosion,
  • Experiment with different proportions of bicarbonate soda to acid
  • Make a mk II using painted red and blue capsule halves, when blue is up it is safe, when red is up it is armed.
  • Make a catapult for them, have fun.

These bombs are completely safe, for the over-cautious eye-protection may be necessary (swimming goggles?) though. Keep them away from small children and animals, you don’t want to get sued do you? Spend one lazy Sunday afternoon mucking around with them in your garden, it gets you out into the open for a while and does it with explosions, what could be better?