Another carbon dioxide question:

When I studied in Germany, there was a time when I lived in a students' dormitory and we had a very small telephone niche on our floor with a door to close in order not to disturb other students by loud talking.

Once after about half an hour of vivid talking with the door closed I felt as if I was going to faint.

I think the air volume in there was only about half as big as in a normal phone booth (their outer measures are 100x100x220 cm in Germany), but the door was less tight.

But I also know that "feeling as if" and really fainting are a long way from each other. I think there are no cases reported of sobre people fainting in phone booths.

How long can one remain concious with, say, two cubic metres of air? Or with one? Or do they have some secret airing system in there?

(good thing everyone has mobile phones now)

I was pealing a Pomelo fruit and suprised by the large space in its center. I wonder what fills that space before air goes in when its pealed.

I bought two gold fish (Gonzo and Princess, my girlfriend named the latter), they are in a simple bowl with no air pump. The pet store suggested I buy oxygen tablets (at the same price of the two fish). All I do is pop one in every two days. It takes about 4hours to dissolve, slowly releasing bubbles. How do they make it, whats it made out of, and do they work?

I know the air inside the lungs makes people float and just like that,the air inside a ship decreases the density of the total volume and hence makes the ship float.But what happens if you vacuum the air inside the ship and then seal it somehow,just like exhaling air from your lungs,does the ship sink cause the density of the total volume will just be the density of them metals inside the ship despite the airless big space in it?

The power of a vacuum is very obvious. Suction pads can defeat the earths gravity and lift a person up off the ground. So why does the vacuum of space not suck the air molecules away from earth, when the vacuum force is far greater than the earths gravitational pull? Am i overlooking something?

I recently saw a video on the internet of some dolphins playing with bubble rings in their water tank. These rings seemed to be just shaped bubbles but how do they form? and what sustains their peculier shape?

Here is a link to an example of the bubbles:

http://www.boreme.com/boreme/funny-2009/dolphin-bubble-behaviour-p1.php