What keeps submarines underwater?
In order to understand what allows submarines to stay underwater, it’s important to first look into why things float on water in the first place. Archimedes showed that an object will float if the weight of that object is less than the weight of the water it displaces. As you may be aware, when you get in a bath you are displacing the water – this causes the water level to rise. The effect is known as buoyancy and accounts for why big steel ships don’t sink.
Submarines fall into two different categories: static divers and dynamic divers. Static diving uses differences in weight to affect the buoyancy, whereas dynamic diving uses speed and power to submerge, a little bit like how aeroplanes fly.
