chemistry question

Hi folks, does anybody know of a way to make alka-seltzer tablets bubble for 20 to 30 minutes? Is there another ordinary household chemical that could be used instead?
I'm trying to think of an emergency-backup locator system for when a ship's recovery float fails to deploy. It is very easy to drop a couple alka-seltzer tablets in your smokestack, but they don't bubble for long enough. I'm wondering if there's a way to extend the bubbling, either chemically or mechanically. So far I'm thinking of pouring powdered alka-seltzer into a brass tube and blocking off the bottom, so only a little of the alka-seltzer meets water at any moment in time.

 

Perhaps vitamin C powder (ascorbic acid) and baking soda (sodium bicarbonate) packed into a straw would be a cheaper alternative.
You could try all sorts of additives to slow down the reaction, both chemically and physically. Sugar comes to mind, but i don't know why.

 

Would limiting how much water reaches it affect things?

 

Tug has a good point, I'd recommend mounting any such device outside the hull, preferably where it won't get wet till the boat sinks.

 

Don't forget about those people who will have a stroke if you put ANY chemicals in the water, doesn't matter if it is safe or not.
We all have run into them at the lake.
J

 

Nope, I am talking about things bubbling out of boats, like alka-seltzer, that some people won't believe are harmless. We had one guy kicked off a lake because the Parks guy said since the boat moves, it must be using fuel and therefore polluting the lake. There are alot of people out there with tunnel vision and see only what they want to.
J

 

I guess the park guy walked right buy the family feeding the geese which in turn leads to tame geese, tame geese eat all the shore-side grass, no grass leads to erosion of sequestered contaminates to the water, and of course, there's all the excess nitrogen from the thousands of geese turds.

Steve

 

Here it is duck turds which lead to swimmer's itch and closed beaches, but as long as it's "natural"!!!
J

 

If you use alka seltzer have your smoke stack have a small hole on the bottom,
example, take a film canister and poke a hole about the size of a pencil lead in the top and bottom of the container and have a alka setlzer as upright as possible,

ground alka seltzer bubbles faster

 

if neccesary make that a couple holes on bottom but as few as possible on top,
air flows easier than water

 

The following is a top-secret report written by the Bitondo Bros Productions R&D Department at the request of the Salvage Department. It apparently describes an initial inquiry into a new technology for marking the location of a sunken vessel for recovery. Although others have suggested similar ideas for marking wreck locations, this is among the first actual tests, and has the further advantage of not requiring a CO2 supply, which many transports and single-shot destroyers lack. Clearly, more research is needed before this technology hits the battlefield, but it shows significant potential that experts in the field say they will watch closely.

-Kotori87



The Use of a Tube to Extend the Bubbling of Alka-Seltzer In Water


Hypothesis: Grinding up alka-seltzer and placing it inside a long, thin tube will limit the amount of alka-seltzer in contact with water and extend the duration of the reaction, creating a slow trickle of bubbles that will last long enough for a sunken model to be located from the surface in the event the float fails to deploy.

Setup: Walgreen's Effervescent Cold Relief Plus was the generic alka-seltzer used to produce the bubble reaction. The tests were performed in a clear glass of water. The water was replaced after each trial. A spare 5/16" ID barrel for the destroyer Z-25, about 4" long, was used as the long thin tube for the experimental test.

Experiment: For the control test, a single tablet was placed in a glass of water and the time from the tablet entering the water to the end of the bubble stream was recorded.

In the experimental test, a single tablet was ground up and poured into the barrel from the Z-boat. One end of the barrel was taped off, so only a single end would let water in. The barrel was placed in a glass of water with the open end up. The time from the barrel entering the water to the end of the bubble stream was recorded.

Data:
Control test: 1:10
Experimental test: 10:20

Results: In the control test, a whole tablet took about 1:10 to dissolve. Less time was required if the tablet was cracked or broken into smaller pieces. The bubbles produced were individually very tiny, much smaller than 1/32", but a thick stream of the tiny bubbles was produced. After about 0:20, the tablet floated to the surface, where it stayed until it fully dissolved.

In the experimental test, a whole tablet took about 10:20 to fully dissolve. Up to roughly the 5:00 mark, a steady stream of several large bubbles per second was produced. By roughly the 7:00 mark, the bubbles had slowed to one bubble per second, and by roughly the 9:00 mark the bubbles had slowed to one bubble every few seconds. The bubbles produced were roughly 3/16" diameter, though some got as large as 1/4" diameter.

Discussion: The bubble stream from the control test is probably visible enough to allow a sunken model to be located from a boat on the surface. The 1:10 duration of reaction in the control test is not nearly long enough, however, for a salvage boat to be launched and go to the wreck site.

Placing the alka-seltzer in a thin tube extends the reaction by a factor of ten, providing more time for a salvage boat to be launched and reach the wreck. The stream of fewer but larger bubbles is just as visible on the surface as the control bubble stream, if not more so. Only a test in deeper water will provide confirmation, however.

Conclusion: The bubbles produced by both of the tests are most likely visible enough to locate a wreck under 8-12' of water. The short duration of the control reaction is not nearly enough for the full recovery process. Placing the same quantity of alka-seltzer inside a tube extended the duration ten-fold. It is reasonable to conclude that the tube caused the change, most likely by the small diameter of the tube limiting the amount of alka-seltzer in contact with water at any time.

This could be tested further by trying smaller and larger tube diameters. Another test could investigate longer tubes with the same diameter allowing more alka-seltzer powder. Yet a third test could investigate using a larger container (perhaps a film canister or pill bottle) with a small nozzle drilled to limit the flow of water and air. As well as investigating how the container affects the bubbling reaction, further tests could be devoted to examining the bubbling chemicals themselves. Specific inquiries of other alka-seltzers, denture cleaner, and combinations of baking soda and various household acids are suggested. Finally, practical deep-water tests must be conducted under actual pond conditions for visibility and the effects of pressure on bubble rate and endurance.

 

A long time ago Lars glued the alka-seltzer to the deck and glued a scout plane catapult with scout plane to the alka-seltzer. In theory the ship would sink, tablet melt and plane pop to the surface all attached with a strip.
In practice the tablet disolved durring battle. The plane came off the ship and drug in the water like a sea anchor. He'd slow down, let the plane pop to the surface then try to move again.

 

Yes, the alka-seltzer does need to be protected from incidental splashes. I plan to try one inside a smokestack. Unless there's a lot of splashing going on, that smokestack isn't going to fill up with enough water until the ship is safely sunk.