A Wonderleaf question
How do submarines dive and float?
a real page from the book
Submarines dive and rise by changing what is inside their ballast tanks. Air in the tanks makes the submarine buoyant, so it stays up. Letting seawater in makes it heavier for its size, so it goes down. Pushing the water out with compressed air brings it back up.
The lovely bit is that a submarine does not need to change shape to move between surface and deep water. It changes its balance with the sea. Small fins help point the bow, while buoyancy does the lifting or lowering.
Wonder words
- ballast
- buoyancy
- pressure
- valve
Try it out
Use an empty lidded bottle in the bath or sink, adding water and air to test when it sinks or floats.
Read the whole picture book
Watercolour scenes, straight answers, about three minutes cover to cover.
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