Time for an Instructable that makes a noise! This Ballistic Bubbles Machine produces soap-bubbles that make a very funny and sometimes very loud crack when ignited. The bubbles contain a mixture of two gasses: Oxygen and Hydrogen.

The mixture of these two gasses is called… oxyhydrogen. In Dutch (and in German too, I believe), the word for oxyhydrogen is the brilliant noun “knalgas”, which can be translated literally as “crack-gas” or "boom-gas". This easy and cheap to build machine shows how appropriate the word knalgas is…

Also, watching the video might show the fun of making and using this machine…

If you're having trouble viewing the video from here, have a look at it on YouTube...

There’s a lot of pretty cool science happening in the Ballistic Bubble Machine. In step 7, some hidden secrets are revealed by using Red Cabbage Magik. The final steps of this I’ble will be about the bubble-science, if you’re curious.

If you’re not curious at all about the science but want to make a totally cool machine, read on! Build the machine and have fun with it. New years eve is so close! When you got all the stuff listed, building will take you about 4 hours, I think. (Lucky you, it took me a hell of a lot longer to figure it all out! This project has been haunting me for a year!)



Grand prize: An Instructables 3 months pro-membership gift-code from me.
Ricalvarez is the lucky winner! Congratulations!

Somewhere in this I’ble is a hidden reference to another, rather famous Instructable. The hidden clue is on one of the pictures in one of the steps. The first person who posts the location of the picture with the hidden clue, the name of the instructable that is referred to and it’s author is the winner. Scoochmaroo and members of a certain family living in the northern part of The Netherlands are excluded from this contest…

1-40 of 120Next »
PLEASE NEVER ADD SALT in an electrolyzer! It creates poison gas.

Huh? Did you knew that Plutonium carbonate is a salt? (Like baking soda, and it doesnt contains chlorine)

Lol, you need to put something in there as an electrolyte. Salt is probably the cheapest of the options. Your "poison gas" is chlorine. Nothing horrible about chlorine, if your electrolyser is not very big and not running 24/7 in a closed space.
El Mano4 years ago
Do the carbon rods corrode? I'm trying to find electrodes that can run continuously for a while without corroding.

For future readers: Carbon rods

ynze (author)  El Mano4 years ago
The carbon rods dissolve slowly. I really don't know how long they will last. The stuff that doesn't corrode at all, is Platinum. Platinum electrodes are used in labs, and are not cheap. A set for use in school-labs cost around €80,- in The Netherlands.
TeslaBoy ynze2 years ago
I use stainless steel machine screws and washers it works well and is cheap, plus its a non consumable electrode material.
You can buy stainless steel hardware at osh or home depot
I wish they sold Stainless steel fender washers at osh so I would have even more surface area for greater gas production, Guess I will have to order some from McMaster-Carr.
TeslaBoy2 years ago
I would use baking soda even though your only making small amounts of gas, Its not good to have chlorine gas which comes from using salt(sodium chloride).

Baking soda is NaHCO3 or KHCO3, no chlorine.

ynze (author)  TeslaBoy2 years ago
I agree and I tried baking soda, but the current (and thus the gas production) through the "baking soda electrolyte" is much smaller compared to the salt-electrolyte.

And because I wanted enough gas to blow bubbles, I returned to salt :-s
TeslaBoy ynze2 years ago
I think a good choice would be magnesium sulfate or potassium sulfate.
And I also think that magnesium sulfate would be easy to find since its used in epsom salts.
I just found out that salt will eventually turn into NaOH or sodium hydroxide which is a great electrolyte and is regenerative as it breaks down into sodium and hydrogen and oxygen but will reform back to NaOH since sodium will bond so easily. So its a non consumable electrolyte. And thus after all the chlorine gas is gone it will turn safe as can be as long as you don't drink it and the only gaseous products will be hydrogen and oxygen.
Wyle_E4 years ago
Actually, those two white cylinders on the space shuttle are solid-fuel boosters. The liquid oxygen and hydrogen tanks are in that fat brown cylinder in the middle.
Most of that huge cloud around the pad isn't from the main engine exhaust, it's cooling water that keeps the steel blast deflector in the flame trench from evaporating like a snowflake.

Back to electrolysis: I've used lead electrodes. Lead is easy to come by, is inactive enough not to be corroded, and you can solder wires to it.
I think there is a detail or two you are forgetting. I have run this reaction quite recently and found that the products aren't oxygen and hydrogen, but rather are hydrogen and chlorine gas. Since this is an aqueous solution of NaCl, the current splits the water, and some of the chlorine binds to the lead, forming insoluble PbCl2, which sinks to the bottom. The rest of the chlorine is released as a gas. Without any chlorine to bind to, the aqueous sodium bonds to a hydroxide ion from the water, and the extra hydrogen is released as a gas at the other electrode. So I personally would not recommend using lead electrodes to do this.
I just checked, and a good option would be to use baking soda instead of NaCl and if you do, then you could stick with using iron or steel. I used a setup like this once to power my own version of the water-bottle rockets :)
But people say you should not use Stainless steel either, because it releases hexavalent chromium into the water.
While that is normally a valid point, I believe it is not a concern in this particular scenario for a few reasons. First, if you use baking soda as the electrolyte in this reaction, the steel should not be corroded while it is used due to the composition of the baking soda. Second, even if it were to in fact be corroded by the reaction, I doubt that any of the chromium compounds would find their way into your body unless you ingested one of the fluids simply due to how the cell is constructed. The chromium would be in liquid state and thus when the gas passes through the tube into the cup, the aqueous chromium would be left behind in the cell. Therefore, while chromium compounds can be given off by steel used for electrolysis, I believe that given these circumstances it is not something to be concerned about.
f.3 pyrorower2 years ago
That's great and all and you seem to know your stuff. What though, should one do to dispose of any contaminated water solution? If it has chromium in it and you put it down the drain even at a small amount, isn't that like poisoning the well in a way? If you dump it outside I know you risk poisoning ground water, your pets or other wildlife and or your garden. So again what do we do with the stuff after the project is over?
Yea, the middle tank that has the oxygen/hydrogen in it is what fuels the space shuttle boosters.
ynze (author)  Wyle_E4 years ago
Thanks for correcting the mistake! I'll write it down better in the I'ble as soon as I find time.

Could you post a pic of the lead electrodes in action?

Thnx again.

Wyle_E ynze4 years ago
I didn't take any pictures. It was decades ago, for a middle-school project.
ilpug3 years ago
I have one question: could you make the gas production a bit faster, so the bubbles could actually get airborne before you blow them up?
rjbatc ilpug3 years ago
You can make the electrolyser larger, with larger electrodes and push more current through the water. That way you can actually make a welding torch. Just google or youtube "HHO torch".
ydkbl3 years ago
at school teacher made the same with salted water and all but result was O2 and Cl then added phenolphthalein to make it red and my question is if i made this bubble machine will result O2 and Cl or O2 and H2 ?
turbonegro4 years ago
Yeah its called "Knallgas"" here in Sweden too
I would like to build something like that emitting pops and crackles
To keep birds from nesting on my roof
You can get 4 big carbon rods from a 6v lantern battery.
budabob074 years ago
Very cool, but I would recommend using an alternative power source instead of batteries, as they can be expensive and they don't put out a ton of current (depends on the battery of course). An old computer ATX power supply can supply 12 volts at 15 amps, and 5 volts at 30 amps.
ynze (author)  budabob074 years ago
Very true! I used batteries to lower the costs and to keep the machine portable, but the batteries are drained quickly. So, for anyone who has a PC power supply at hand...
techno guy4 years ago
How fast will it be if you use 8 electrodes?
ynze (author)  techno guy4 years ago
Give it a try :-)
warlock404 years ago
Great Instructable!.. the family had a great time working on this project.
I see what you mean about sealing up the jar.. that was the biggest obstacle. I had used a slightly wider jar with a plastic lid.. which made it a tad hard to seal. We ended up using model clay around the edge which did the trick.

We got all but the tube and Silicone at the dollar store.. in total about $30.
The Carbon Zinc batteries were indeed at the dollar store but also found a bunch in batteries that came with the kids toys. (You know the cheep ones) They were marked 0% mercury but had a R### code on them. The best part about these is once you remove the metal sheath there is a plastic coating. If you cut the plastic all the way around and then gently twist and pull you will pull the entire carbon core right out of the top.

I am looking forward to some modification and generation 2 next weekend as family project.

Thanks for the instructable
ynze (author)  warlock404 years ago
I'm glad to hear you had a good time building it! Could you post some pics of the result?

Thanks for the comment!

warlock40 ynze4 years ago
The original had some seal issues.. I had some difficulties with getting an airtight seal as I noted.. so I used clay to seal it up around the edges.

The batteries were a breeze once I got the hang of it.. you can see here there were a couple casualties.

I took some from the video we made which I hope to get around to editing for youtube shortly and made stills

Last weekend we resealed the top by slathering silicone over the lid and base then cutting out around the tube. Our next goal is to verify a good seal and carry on with some more tests.

We are throwing around the idea as noted in one of the comments try and pump a small amount into an upside down jar in a bucket. The idea is to displace the water with the oxygen and hydrogen. we are throwing around the idea of using a pump of some kind to suck it out of the jar from under water and into a balloon... not sure whether it would work.. but worthy of discussion..

My son wants to make something like a home made rocket out of it..

I'm not certain it will float but it should make a nice boom as a finale if we could get it into a balloon.

The last three pics are of the updated lid with the extra silicone... It has been a great deal of fun thanks again.
ynze (author)  warlock404 years ago
Thanks so much for the post! Wonderful, really! Great to see how you used the instructable and made the project your own. Thanks again!
sparda_684 years ago
hey i love electrolysis and what it can do with simply water. if you wanna get more "bang for your buck" try separating the cathode (+) and anodes (-) and collecting the bubbles from each of them in different areas because the cathode is what makes the hydrogen and the anode makes oxygen. and if you can figure it out try catching the pure hydrogen in a balloon if shuld float like helium but if you get a long enough stick with the end on fire and poke it it explodes in a massive ball of fire :) have fun, be safe, and happy science experiments all
audiophile4 years ago
why are there 4 electrodes? couldnt the job be done with just 2?
ynze (author)  audiophile4 years ago
Two electrodes instead of 4 will work too. Only less gas will be produced, so you'll have to wait a bit longer for the bubbles.
I liike!!
Hmmm.... perhaps if I connect it to a potato cannon.....
ynze (author)  Loosewire; SOE Operative4 years ago
Exactly! :-D

Make a Ballistic Bubble Spud Gun!
Yes, it may prove to be better than hairspray as it wouldn't cause as much fouling.
1-40 of 120Next »