You might think that the air capacity in a scuba tank reduces as you descend if you read the PADI Scuba Diving Instruction Manual or watch the DVD. I am 99% certain that this is incorrect and that the air volume remains constant. Even though none of them could explain how the air in a rigid, sealed tank could be impacted by outside air pressure, the instructor, dive master, and the other students all agreed with the handbook when I brought it up during the in-person scuba lessons.
When I heard these explanations of what was taking place, I realized something was wrong:
- The pressure from the tank’s exterior was, in fact, permeating the tank’s interior due to osmosis. The issue with this is that osmosis would necessitate porous aluminum or steel tank sides. They’re not.
- The remaining space in the tank is a vacuum since the volume of the air is decreasing. The issue with this is that since a vacuum is a low-pressure area, it is unclear how high-pressure air and a vacuum could coexist in the same space.
I struggled for a while to find a suitable phrase to express how I was approaching the issue, but I finally did.
- Imagine touching someone’s forehead with your finger. In essence, you are exerting pressure in a similar way to how the air (or water) around us does. Of course, you’re only exerting pressure in a small region.
- A sponge between your finger and the target’s forehead won’t stop the pressure from being felt by the target. This is due to the fact that your finger is pressing on the sponge, which is then pressing on the person.
- Instead, if you have the individual stand on one side of a wall while you are on the other, you can push against the wall all you want without the other person feeling a thing. The wall’s rigidity is the source of this. The wall distributes the entire amount of pressure you’re putting with your finger throughout its surface. A scuba tank operates in this manner. The volume of air inside the tank remains constant since the water pressure isn’t high enough to distort the tank walls (until you start sucking the air out of it).
