When exhaling underwater, why do multiple bubbles come out and not a big one?
In: Physics
The surrounding water pressure, pushing on the air, wants to compress it into a shape where the forces all balance out: a sphere. The air, being so much lighter than water, wants to move upward. Those processes combine to break up the air stream into little approximately-spherical bits. As you blow more air out, the previous air has already been surrounded by water and has risen too far away for more air to enter it.
If you scuba dive, if you are capable of ascending approximately as fast as the bubble you can keep enlarging it. The same forces are doing the same work, but if your movement never lets the bubble get far enough away for the water to pinch it closed, it just keep expanding.
Dolphins do this, as well as blowing air rings, which they then chase upward. They even play around to see who can swim through the rings or ‘pop’ the bubbles (breaking them into a cloud of smaller bubbles).
Latest Answers