[local] gourmet air tasting
Nitrogen makes up almost 80% of the atmosphere, with oxygen taking 20% and everything else totalling to a couple of a percent. The nitrogen is mostly inert, so you can replace it with another mostly inert gas, say, helium.
If you then filled a large enclosed space up with this mix, say, a sealed mattress bag, you could sit in there and breathe it for 10 minutes with no ill effects. You would, however, sound like Alvin and the Chipmunks the entire time.
savorie and I did this last weekend, and it was gobs of fun. However, I have a lot left over, so let me know if you want to try it. I have to give the tank back by Thursday, so we'd have to do it either tonight, or very late tomorrow night.
If you then filled a large enclosed space up with this mix, say, a sealed mattress bag, you could sit in there and breathe it for 10 minutes with no ill effects. You would, however, sound like Alvin and the Chipmunks the entire time.
savorie and I did this last weekend, and it was gobs of fun. However, I have a lot left over, so let me know if you want to try it. I have to give the tank back by Thursday, so we'd have to do it either tonight, or very late tomorrow night.