How submarine sink or float on water?

Submarines sink or float by adjusting their buoyancy through the use of ballast tanks. When water is pumped into these tanks, the submarine becomes heavier than the water around it, causing it to sink. Conversely, to float, the submarine expels water from the ballast tanks, reducing its weight and allowing it to rise to the surface. This ability to control buoyancy enables submarines to navigate underwater and at the surface efficiently.