A Wonderleaf question
How do submarines dive and float?
a real page from the book
Submarines dive and float by changing what is inside their ballast tanks. When the tanks hold air, the submarine is buoyant and stays up. When seawater fills them, the submarine becomes heavier for its size and sinks under control.
To rise again, the crew sends compressed air into the tanks, pushing seawater out. Small fins help set the angle while the submarine moves. The whole trick is careful control of density, the same reason a full bottle sinks more easily than an empty one.
Wonder words
- ballast
- buoyancy
- density
- pressure
Try it out
Put an empty capped plastic bottle in a sink, then add water inside and compare how it floats.
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