Hello,

I would like to make a simple homemade biosphere, but from what I understand, the oxygen can run out because of organisms using it. Is there some sure-fire way to prevent the oxygen from running out and/or is there some way to measure the oxygen level so I can open the biosphere before any organism suffocates?

Thanks, LiveMatter

Originally posted by LiveMatter
I would like to make a simple homemade biosphere, but from what I understand, the oxygen can run out because of organisms using it. Is there some sure-fire way to prevent the oxygen from running out
Lots of plant life.. i.e. a surface area to atmospheric volume ratio near that of the earth (which is virtually impossible -- that's why biospheres are as huge as possible).
and/or is there some way to measure the oxygen level so I can open the biosphere before any organism suffocates?
A simple oxygen sensor will do this. You can build one yourself if you'd like. Here's one very similar to the one I use for analyzing my gas mixture when I do mixed-gas scuba diving:

http://oxycheq.com/El_Cheapo_Main_Page.html

Beware that you'll also have to mind the carbon dioxide levels...

- Warren

This seems like it will do the trick. I don't know much about the carbon dioxide though. Any suggestions?

Originally posted by LiveMatter
This seems like it will do the trick. I don't know much about the carbon dioxide though. Any suggestions?
You can probably buy or build a carbon dioxide detector -- I don't know offhand how though.

- Warren

Good suggestion.

Insert oxygen in measured amounts. The experiment will work just as well. You measure the air going in and the air going out and check for discrepencies.

Appreciate it!

Originally posted by Clockwood
Insert oxygen in measured amounts. The experiment will work just as well. You measure the air going in and the air going out and check for discrepencies.
A constant mass flow will not guarantee a particular oxygen concentration.

- Warren