How do submarines dive and float?
The Breathing Boat
How do submarines dive and float?
A submarine is basically a giant metal bottle that can sink on purpose — and then come back up whenever it wants. How does a several-thousand-ton hunk of steel decide whether to float or drop like a stone?
The secret is inside: huge tanks called ballast tanks run along the sub's sides and belly. When the sub floats on the surface, those tanks are full of air — and air is incredibly light. The air makes the whole submarine less dense than water, so it floats, just like a beach ball bobs on a pool.
