Hydrostatics is a branch within Fluid Mechanics that studies a fluid that is rest. It also studies the pressure within a fluid as well as the pressure on immersed bodies. Both compressible and incompressible fluids are studied as part of hydrostatics.
While you are studying hydrostatics you will gain an understanding of pressure. More specifically you will learn how to determine what the pressure is at a certain point as well as gain an understanding of what a pressure field is. You will also see how pressure variations of a fluid at rest effect both an incompressible as well as a compressible fluid. Also, you will learn how you can use these hydrostatic pressures to gain a mechanical advantage.
In addition to learning about pressure you will also learn how to measure pressure with different devices. Some of these devices are manometers.
Finally, you will also learn what buoyancy is, and how hydrostatics is used to calculated buoyancy. As well as how stable a floating object is.