The idea is that CO2, when mixed with water, forms carbonic acid. The acidity of water can be estimated using chemical solutions of visual indicators (or you can get a more exact reading using digital meters), for example, the chemicals used to measure the acidity (pH) of swimming pools such as Methyl red.
So it would, I think, be a useful test to simply pump ambient submarine air through a bit of water containing some methyl red. I have tested the effectiveness of this in a very preliminary way by blowing into a water/Methyl red solution with a straw. The solution turns red almost instantly, within a couple of breaths (thats ok, there is lots of CO2 in my breath and I am comfortable re-breathing the same air a few times).
What I want to see is how long it takes for the solution to turn red by pumping through ambient air from a sealed chamber (rather than directly from my breath). Or if you prefer: how red the solution gets when a person sits inside a sealed chamber for an hour or so (or whatever length of time they are comfortable with).
I would suggest that a simple fishtank pump would be very sufficient ($10?). Hopfully any O3 from the electronics wont be significant, though that too may be important to detect since it is toxic. Methyl red is cheap and simple to obtain from a swimming pool chemical dealer ($2). If people dont approve of chemical indicators, they could splurge and fork out for a more expensive and more exact digital pH indicator. I would be interested in hearing about results from that too.
In any case, that is all there is to it. I dont think it is TOO foolish and it might be useful yet. Let me know if pictures would be helpful, though I dont think there is any one way to pump air through a jar with a bit of water.
EM.P.S. While I have peoples' attention, has anyone read the book 'stars beneath the sea'? I absolutely reccommend it, though it is entirely focussed on the science, history and evolution of scuba. There is not a whole lot to do with submarines:
http://www.bluebeyond.com.au/reviews/br-stars.php Pierre Poulin wrote:
I volunteer!My sub is air-tight. And I don't think we should go off-list. the more people involved, the better I think!Pierre "air-tight" PoulinFrom: Erik Muller <emuller@naic.edu> Reply-To: personal_submersibles@psubs.org To: personal_submersibles@psubs.org Subject: [PSUBS-MAILIST] test of CO2 safety hardware - any volunteers? Date: Thu, 12 Feb 2004 08:38:19 -0400 Hello Folks,I have a quick request for people with a functioning pressure hull (i.e. does not need to be a finished sub, just airtight) to see if a simple idea for measuring ambient CO2 content is useful. Its a VERY cheap system, and should work as a first-order indicator (i.e. not exact, but sensitive). Please email me offlist if you are interested and I can explain my idea. I might even draw some pictures.EM._________________________________________________________________MSN Search, le moteur de recherche qui pense comme vous ! http://fr.ca.search.msn.com/