I have long wanted to build a baking powder submarine from commonly available materials. I had one of these in the 1950s when Kellogg's gave them as a prize in cereal boxes. Those were a little over two inches in length. A couple of years later l saw a much longer one in a store window. Mr_o_uk got me thinking about it again with his Baking Powder Diving Submarine Instructable, but his is a concept submarine he has not actually built. There are some practical problems I had to solve before my concept would be a working bathtub submarine that goes to the bottom, rests there, rises, discharges a bubble of CO2, and sinks to the bottom again in endless cycles until the baking powder is depleted. I have done that in a way someone reading this Instructable can replicate.

Step 1: Materials and tools

The bulk of the submarine is made from a gray PVC nipple nominally 1/2 inch by 6 inches. (The actual internal diameter of the PVC is a tiny bit more than 9/16 inch.) 

All materials--
  • 1/2 x 6 gray PVC nipple
  • Wine bottle cork (synthetic [plastic], not real cork)
  • Sheet metal screw
  • Axle cap for a 1/2 inch axle
  • 5/8 inch internal diameter (nominal) braided rubber hose (actual internal diameter measures about 9/16 inch
  • Hot glue
  • Finish nail
  • Clear finger nail polish
  • Baking powder (not baking soda)
  • Fine tooth saw
  • Sandpaper
  • Screwdriver or nutdriver
  • Drill and bits
  • Dremel tool and burring bit
  • Grinder and wheel
  • Knife
  • Hot glue gun
  • Side cutter pliers
<p>Nice project. Can't wait to make this one! But can a propeller be added so the submarine can move (without affecting the manner of rising and diving)? thanks :)</p>
Trying to add propulsion would add all sorts of complications, including weight and balance, especially if a battery and a motor would be involved. I did another Instructable on a small boat propelled by an Alkaline-Seltzer tablet inside a 35mm film canister. (When the boat is tipped to horizontal, water inside the canister is able to mix with the tablet and make lots of fizz that escapes through a tube at the rear end of the boat.) You might be able to add a propulsion system using that. <br>It has been a long time since I was a boy playing with the free Kellog's cereal submarines and I do not remember everything about how those functioned, I have found this submarine does not sink well during the first few seconds until the baking powder settles down and produces gas at a more moderate rate than at the very beginning of a new charging load of baking powder.
Oh, okay. I will try to add the alka seltzer method as propulsion system. Thanks :)
<p>Does it matter if the water is hot or cold?</p>
I have always used water just as it came from the faucet--neither hotter or colder than that.
<p>hello Phil B.!</p><p>I just finished the Baking Soda Submarine and it works great. I had to change the design a little to accommodate the materials I had in hand</p><p>1. I used a soda cap for skirt for holding the gas.. I had to use a washer for the plug of the &quot;baking powder reactor&quot; so my model was a little on the heavy side. I will try to work the weight problem on a second submarine. </p><p>2. Another problem I had was that the submarine would not tilt to release the bubble due to the weight of the washer so I glued a little wood plug on the side of the reactor to help the tilting and releasing the bubble</p><p>3. I have to keep on sanding the bottle cap so it does not have to tilt as much for releasing the bubble</p><p>Congratulations as it is an easy project and a very fun one! Thankyou very much as the baking Powder Submarines have always amazed me</p>
<p>here are a couple of videos of the submarine in action. Just a tiny change in the cap position and it behaves diferently. ENJOY!</p><p>http://youtu.be/GMnBUF4WMBY</p><p>http://youtu.be/OA5AjXWMfWw</p>
Thank you for trying this project and for reporting your results, as well as sharing your modifications. I am very pleased for your that it works. It is a joy to hear from you.
wonderful science..
video link is not playable..
The video link is good. If you read the text below the photo you know not to click on the photo, but on the hot link in the words below the photo.
Does anyone remember the little boat you used a candle and water to propel around a sink or bathtub? Hope someone makes an instructable for one
I don't know if there are any on Instructables, but you can find a variety of designs on the internet and in old children's magazines (from when we actually trusted our children to build things.) <br> <br>They are very simple and can be made with nothing more than a boat that can hold a candle and a coil of copper tubing. More efficient designs can be found with a little research.
I made a little boat powered by the bubbles from an Alka-Seltzer tablet inside a 35mm film canister in contact with water also inside the canister. You can see it <a href="http://www.instructables.com/id/Alka-Seltzer-Powered-Bathtub-Boat/" rel="nofollow">here</a>. I hope it is close to what you have in mind, even though it does not use a candle.
this is really great. an ideal project for my 6 yr old and me. Thanks for making this ible.
Thank you for looking and for commenting. I looked at customer reviews for commercially available small submarines of this type. Some found their small children were enthralled by a baking powder submarine, while others found small children in their families tired quickly of this water toy. I hope it goes well for you and your 6 year old.
I got such a kick out of reading this. I played with something like this 50+ years ago. My mother got so mad when I left the can of baking powder i the bathtub!
I am glad you enjoyed reading this. We are close to the same age. You probably had some of those Kellogg's issued in the mid-1950s. There was no extra money in the average house at that time. It is not surprising that your mother would have been angry about replacing a can of baking powder, although it is funny now. <br> <br>I just wanted to see if I could make a working example of a baking powder submarine that others could copy if they chose to do so. I had no idea how many people would respond to it based on reliving personal childhood experiences.
Cool! I had a couple of the 2&quot; Kellogg plus a 6&quot; Nautilus you had to send away for. There was also a 6&quot; baking powder powered PT boat.
Some of those are still available at times on eBay, but they cost considerably more now. Thank you for your comment.
Phil, you should put a video of it &quot;swimming&quot;. <br> <br>I remember when many years ago (I was a child) Popular Mechanics published a baking powder submarine. It was made of galvanized sheet, a lot more complicated than yours.
Osvaldo,<br> <br> I did a search for a baking powder submarine in <u>Popular Mechanics Magazine</u>, and found this from <a href="http://makezine.com/2007/08/26/the-mysterious-submarine/" rel="nofollow">MAKE Magazine</a>. It uses carbide tablets to produce (flammable) acetylene gas in water. To see the full original article from the December 1924 Popular Mechanics (p. 999), go to <a href="http://books.google.com/books?id=JdsDAAAAMBAJ&q=submarine#v=snippet&q=submarine&f=false" rel="nofollow">this link</a> and scroll down to the heading for &quot;A Mysterious Submarine.&quot; Then click on the highlighted page number, which is p. 999.
Bill, I think it was not that article, but not sure. My memory is a bit moth-eaten ... <br> <br>Thanks for the link, is very interesting.
I did a search and found the same artucle,lol.The one I was thinking of with soup cans was in an old 2&quot; thick book of projects I have packed away somewhere.The title escapes me,if I find it,I'll post the title.There is also an electric one in the May '32 issue,I guess it could be adapted to more modern batteries(LiPo,etc.)
I think I remember the same article! But the one I remember consisted of soldering soup cans together and ran on carbide.I know googlebooks has them back to the 20's-30's for PM and PS,if I find the article,I'll post it.
I posted it in response to rimar2000. Look below.
Osvaldo, <br> <br>I am thinking about a video, but would have some problems to solve to make the video show what needs to be shown. My PVC submarine is heavier in water than I thought it would be. Galvinized sheet metal would be even heavier. Even though a buoyancy balance can be found, the additional mass adds to inertia and makes the submarine sluggish and slow to respond. That is my theory. Thank you for looking.
Great instructable! I had one of those when I was a kid (had forgotten all about it) and will be following your instructions to build one of my own. Thanks!
Thank you for looking and commenting. Please report back with a picture or two when you have it working.
WOW, haven't thought about this is years! I also had one and it was a pure joy to play with.... Great post. Thanks...
You are not too old to make one and enjoy it again. Thank you for looking and for commenting.
I did make a video and linked it in the last step. Those who have looked and commented will now be aware of the video. <a href="https://vimeo.com/72451715" rel="nofollow">Here is the link</a>.
I love this and my little boy will never leave the bath after I make him one. Thanks! It looks great and great, easy to follow directions. When I have a moment (I have an eco-build to finish too) I will make one although from different tubes I think. Good post thanks!
Thank you for your comment. Many materials will work so long as you can tune the buoyancy so the submarine just crosses the threshold at which it will sink by itself. The baking powder runs out before long, and will need a consenting adult to replenish it. There is some built in control on getting the kids out of the tub!
Love it! We used to build these out of potatoes!
Yes. I never did, but I did include a link to a YouTube video about the Spudmarine. It is a submarine made from a potato. There is also a version made from a carrot.
how it works???
Some of the links in the Instructable give some detail on how it works, but here is a very simple explanation. When water comes into contact with baking powder (not baking soda), carbon dioxide gas bubbles form. The submarine is tuned to be almost buoyant in normal water from the pipes in your home. As it rests on the bottom of a water container, a bubble of carbon dioxide forms under the submarine. When the bubble is large enough, the submarine becomes buoyant and it rises to the surface. The submarine tips a little to one side and the bubble escapes from under the submarine. It is no longer buoyant and sinks to the bottom of the water container. It does this until the baking powder is too depleted to make carbon dioxide in sufficient quantities.
Someone should make this using a 3d printed submarine.
I linked an Instructable in the Introduction, and that Instructable is the plans for a 3-D printable baking powder submarine. As I mentioned, it is a concept. It has never been built. If someone wanted seriously to make an Instructable on a functioning 3-D printed submarine, a prototype would need to be made and tweaked until the buoyancy was just right. Then the working prototype would need to be digitized for printing. My experience tells me this submarine will not work without testing prototypes in actual conditions, unless someone is very good with the right kind of engineering.
Ah sorry I missed that on my mobile.. still a great instructable none the less.. thanks for posting it.
Thanks for looking and for commenting. I did actually compose and post an entire Instructable on my smart phone. It worked, but some things just do not work as well. That is for certain.
Thanks for the memory. In the '70s, I used to have one of these that used two different colored tablets (blue &amp; white) to provide the reaction needed to make the gas bubble. My cousin had a similar device shaped like a scuba diver. We had them outside in snow melt one April and the cycle time was over 20 minutes. Inside the bath tub the cycle time was well under 10 seconds when the tablets were fresh. Thanks again.
Thanks for your comment. As I mentioned to Dawg065, these were released twice: once in the 1950s and once in the 1970s. On the page I linked in the last step the author said is often asked about propulsion tablets. He did not mention two colors, but said those of which he knew were actually made of compressed baking powder.
Neat! I remember those.
They are still fun. While you can purchase a newer version at Amazon any day of the week, reviewers say it does not sink, which is essential to its function. (A buyer could add a little weight with hot glue and BBs or chunks of lead fishing sinkers.) Thanks for the comment.
not bad.i remember getting one of these in a box of Captain Crunch.those where the day when cereal prizes weren't cheap junk like they are now.
If you remember the one that came in Captain Crunch, you had a 2nd release submarine from the 1970s. Our kids were very young in those days and the cereals we fed them did not include these submarines as prizes. I remember them from Kellogg's cereals back in the mid-1950s. At that time the USS Nautilus was the first nuclear powered submarine and it was a very big deal. The cereal prize submarines from that time were a close replica of the Nautilus. Anyway, thank you for looking and for commenting.
Impressive work. Must have been satisfying building it, and especially satisfying once you got the bouyancy balance right?

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Bio: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying ... More »
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