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…

Step 1: Safety and an overview

Some people might want to build a machine like this. Building it is fun, and popping bubbles is hilarious, but, before you start...

Oxyhydrogen / knalgas is an extremely flammable mixture of gasses. The gas will explode immediately when ignited. This Ballistic Bubbles Machine produces soap-bubbles filled with oxyhydrogen on a surface of water. When ignited, the bubbles will explode with a crack, but without much energy. The fact that the bubbles are small makes this apparatus safe to use.

So, in a nutshell:
  • NEVER (and I mean Never) LIGHT THE GAS

Kids might enjoy the machine, but shouldn’t be allowed to play with it without an adult who is familiar with the machine and feels a responsibilty towards the kids being safe. Anyone operating the machine or being in close distance to it should wear safety glasses!


Understood? Sure? Did you see both pictures with this step?

Okay then, proceed to the next step and start building!
PLEASE NEVER ADD SALT in an electrolyzer! It creates poison gas.
<p>Huh? Did you knew that Plutonium carbonate is a salt? (Like baking soda, and it doesnt contains chlorine)</p>
Lol, you need to put something in there as an electrolyte. Salt is probably the cheapest of the options. Your &quot;poison gas&quot; is chlorine. Nothing horrible about chlorine, if your electrolyser is not very big and not running 24/7 in a closed space.
Do the carbon rods corrode? I'm trying to find electrodes that can run continuously for a while without corroding.
<p>For future readers: Carbon rods</p>
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 &euro;80,- in The Netherlands.
I use stainless steel machine screws and washers it works well and is cheap, plus its a non consumable electrode material. <br>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.
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).
<p>Baking soda is NaHCO3 or KHCO3, no chlorine.</p>
I agree and I tried baking soda, but the current (and thus the gas production) through the &quot;baking soda electrolyte&quot; is much smaller compared to the salt-electrolyte. <br> <br>And because I wanted enough gas to blow bubbles, I returned to salt :-s
I think a good choice would be magnesium sulfate or potassium sulfate. <br>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.
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.<br>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.<br><br>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.<br>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.
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.<br>
Thanks for correcting the mistake! I'll write it down better in the I'ble as soon as I find time.<br><br>Could you post a pic of the lead electrodes in action?<br><br>Thnx again.<br><br>Ynze
I didn't take any pictures. It was decades ago, for a middle-school project.
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?
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 &quot;HHO torch&quot;.
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 ?
Yeah its called &quot;Knallgas&quot;&quot; here in Sweden too<br>I would like to build something like that emitting pops and crackles<br>To keep birds from nesting on my roof
You can get 4 big carbon rods from a 6v lantern battery.
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.
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...
How fast will it be if you use 8 electrodes?
Give it a try :-)
Great Instructable!.. the family had a great time working on this project.<br>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.<br><br>We got all but the tube and Silicone at the dollar store.. in total about $30.<br>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. <br><br>I am looking forward to some modification and generation 2 next weekend as family project.<br><br>Thanks for the instructable
I'm glad to hear you had a good time building it! Could you post some pics of the result?<br><br>Thanks for the comment!<br><br>Y.
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.<br><br>The batteries were a breeze once I got the hang of it.. you can see here there were a couple casualties.<br><br>I took some from the video we made which I hope to get around to editing for youtube shortly and made stills<br><br>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.<br><br>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.. <br><br>My son wants to make something like a home made rocket out of it..<br><br>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. <br><br>The last three pics are of the updated lid with the extra silicone... It has been a great deal of fun thanks again.<br>
Thanks so much for the post! Wonderful, really! Great to see how you used the instructable and made the project your own. Thanks again!
hey i love electrolysis and what it can do with simply water. if you wanna get more &quot;bang for your buck&quot; 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
why are there 4 electrodes? couldnt the job be done with just 2?
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!!<br>Hmmm.... perhaps if I connect it to a potato cannon.....
Exactly! :-D<br><br>Make a Ballistic Bubble Spud Gun!
Yes, it may prove to be better than hairspray as it wouldn't cause as much fouling.
24.776 views ;) amazing
It is, and I totally enjoy it :-D. The newsletter of jan. 2nd helped a big lot.
Any idea how stable HO2 is? Does it eventually break down into just water and oxygen? Could you collect this for months or would it break down?<br><br>I'm wondering how realistic it would be to create a solar powered generator that runs on the gas produced by a simple solar cell and water. If it's easier (albiet more dangerous) to store than the small flow of electricity coming from a solar panel, I wonder how realistic this could be? My suspicion is that after a week of sunlight, you'd get about a minute of generator power, though...
The pic of Hoffman's apparatus renders totally funny. Here's the link:<br>http://en.wikipedia.org/wiki/Hoffman_electrolysis_apparatus
You generate and store H2 and O2 seperately, using a Hoffman apparatus (aka Hoffman Voltameter). See pic.
You started me thinking of a way this could be used to inflate bigger bubbles that could then get air born. I'll try and paint a picture of my hmmm illusive idea. Have the gas generator deliver gas in to an upside down (very small) bucket with the bucket having a pivot point just above half way. The bucket would be submerged under the soap solution. With luck as the bucket reaches a certain volumn of gas it would invert delivering the whole bigger bubble to the surface. Not sure if this mix is lighter than air though. If it is then great, as the bubble will leave the surface. Encase the whole soap and bucket arrangement in a fly killer type mesh so that as the bubbles hit it they will spark and pop.
Hydrogen is definitely lighter than air (remember the Hindenburg zeppelin?). My guess is that the knalgas-mixture is lighter than air too. Your idea sounds promising, i'm curious for the drawing. I'm figuring out a way to launch rockets at the moment....
the mixture should be lighter than air as it is 2/3 hydrogen which is the lightest gas (half the mass of helium) and the 2/3 will cancel out that oxigen is (slightly) heavier than air... besides that, in school our chemistry teacher once let a baloon fly which was filled with knallgas and lighted it... nice bang
Sure it was Knalgas, and not just hydrogen?
Well that was really one of my questions. I know hydrogen is much lighter than air but don't know if this particular mix will be.

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