Baking Powder Diving Submarine





Introduction: Baking Powder Diving Submarine

About: I studied Maths and Computing, worked in an Operation Research department, retrained as a civil engineer, worked on site for some major projects. I'm learning to be a structural engineer at the moment! I've ...

This is a classic toy from the 1950s (given away free in cereal boxes) that you don't see around much anymore.

I remember my dad getting me one when I was a boy in the 1980s, but haven't really seen them around since.

After doing some research, here is a really good comprehensive website dedicated to them:

On this website it states that there is no 'clear answer' as to how to make your own baking soda submarine. Well, now with 3d printing technology, the answer is simple - model and print it!

Date Made: June 2013
Approx Cost: (Cost of printing?)
Approx Time: 3 hours modelling (plus printing time)
Difficulty: Easy/Medium

(Note: image taken from under fair usage)

Step 1: How to Operate

First fill a container with water (about 6 or 7 inches).

Next You fill the small compartment of the submarine with baking powder and put the lid back on. These toys use baking powder not baking soda. (I presume it is the same terminology in the USA?)

Then launch your submarine - place it in the water and give it a quick shake, ensuring that the lid doesnt come off. The submarine will sink. After a short amount of time it will float and then it will repeatedly sink and float.

Here is a video showing you one working:

(Note: image taken from under fair usage)

Step 2: How It Works

The sub should naturally sink in water.

Baking powder is a mixture of cornstarch plus powdered acids and bases. The baking powder mixes with the water and creates carbon dioxide gas, by way of a chemical reaction.

This gas builds up until there is enough to make the submarine more buoyant and hence causing the submarine to float.

The submarine will get to the top where the gas will be released and so it sinks again.

And then the process it repeated.

(Note: image taken from under fair usage)

Step 3: The Model

I have built a 3d model of a submarine with the correct holes, compartments and a lid, hopefully ready for 3d printing.

The model is approx 130mm x 20mm x 30mm

This was done using tinkercad and can be found on their website by searching for "baking powder diving submarine" or here:

Please feel free to copy and tinker with it yourself.

I guess really this should be classed as a prototype, as I am unable to print, test and optimize.

Obviously the material used and the size of it (whole submarine and bubble chamber) will affect the buoyancy and hence how long it takes to float/sink etc.

Step 4: Optimization

As I said, I do not have access to a 3d printer (hence why I would like to win one), so am unable to try it out and to optimize the design.

If this model does not work very well, the next step is to analyse, evaluate and adjust the model.

Depending on whether the submarine is not floating or not sinking, then a number of alterations can be made to alter the buoyancy:

1. Make the bubble chamber smaller/bigger (by making partition thinner or thicker).
2. Make the submarine wall thinner/thicker.
3. Make the triangular 'base' smaller/bigger (wider/longer).
4. Make the holes in the body smaller/bigger (top and bottom).
5. Move triangular base and turret along sub length (to balance sub).
6. Alter ratio of powder area to bubble chamber (by moving partition up or down).

The aesthetics could be changed, but I would do this before optimizing, as it may change the buoyancy etc as well.



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    12 Discussions

    Here is mine from the 80's. Still going strong.


    Does the temperature of the water matter? I'm curious how different the reaction will be if the water is hot vs. cold.

    1 reply

    Cool instructable! A bunch of us were sitting around trying to think of what to do with our 3d printer and thought of this, but then happened to see yours on Instructables, the day after you posted it! At any rate, I printed it out, and it seems that the tolerance for the inner part of the plug for the baking powder is a bit too tight. The top part is the same size as the matching bit on the submarine, but the bottom part seems to be too large to fit inside the hole. I'll measure it out and let you know the fix when I get back to my calipers...

    1 reply

    I have checked and overlaid the model and you are quite right, Thanks.

    The plug was made with a solid shapes, whereas the sub funnel was made with a tube, which meant that the profiles didn't quite match.

    I have corrected the lid in v1 to match the funnel. I have also done a v2 changing the funnel to match the lid. So if you are just going to print the lid again, don't do it from the v2.

    Have you actually tested it in water yet? Id love to know if it works and what the buoyancy etc is like...

    I had several of these in the mid-1950s. My brothers and I thought they were great. I have no idea what happened to those we had. The USS Nautilus was the big new thing in those days, and these little baking powder subs were a replica of it. I do remember traveling to Chicago with my parents when I saw one in a toy store window that was almost a foot long instead of the usual two or three inches for the free version. I have often wondered if it would be possible to make one. I do not have access to a 3-D printer, though. It would be somewhat similar in principle to a Cartesian diver.

    4 replies

    I haven't seen those Cartesian divers before. My nephew would like that! Maybe I will give it a go with him next time I go round. Thanks.

    After posting my comment, I looked around the Internet and found several versions of homemade baking powder submarines. One was made from a chunk of potato. Another was made from a carrot. And, there was one made from a full can of diet soda with a section of a plastic soda bottle telescoped onto it, but that one did not seem to use baking powder. I found some with a general search and some by looking at YouTube. The goal seems to be to make the body of the submarine almost buoyant, but not quite so that it sinks slowly to the bottom of the tank. Then a bubble from baking powder in contact with water provides just enough lift to raise the submarine. Small wooden parts, like a conning tower, can be added and trimmed to increase the buoyancy to just the proper amount.

    I remember the little free submarines we had were a little over two inches long. There was a cylindrical chamber underneath that was about 5/16 inch in diameter and 1/4 to 5/16 inch deep. There was a metal cap shaped like a man's hat and it had a small hole in its top. The user filled the chamber with baking powder and put the cap in place with the hole in the cap pointed upward. The submarine would sink to the bottom. In a few minutes a bubble would form inside the metal cap and the submarine would rise to the surface. On the surface the submarine would roll over on its side, discharge the bubble, right itself, and sink to the bottom of the tank.

    Thank you for the memories.

    Yeah, I saw the potatoe one when I was researching (see the picture and reference link on step 2 - not sure if that's the same one you found?), but it just didn't have the same appeal to me as something that looks like a submarine, hence the 3d model.

    I'm glad it brought back good memories. There must have been a lot of households that had them in the 50s and 80s!!

    The potato submarine was from MAKE Magazine, Issue 26. That is what you referenced in step 2. I remember that I could hardly wait until we emptied one cereal box so our parents would buy another and we could have another submarine. I had two brothers, but no sisters. Each of us wanted his own submarine. Our parents did not see a need to buy extra boxes of cereal so we could open them to grab the prize inside.

    ha ha ha, I remember Kelloggs putting these in frosted flakes and fruit loops in the 80s. I'm sure I still have some packed up in my kiddy crap out in the shed. Thanks for the memory.

    1 reply

    Yeah, I think the one my dad gave me in the 80s was probably from Kellogg's too. Not specifically these, but I remember fishing around in the cereal trying to find the toys. My mum always used to say whoever 'poured' out the toy got it. Yeah right! Get your hand in there and find it!!!