A small iron nail sinks in water, whereas a huge ship of heavy mass floats on sea water. Astronauts have to wear a special suit while traveling in space. All these have a common reason called ‘pressure’. The intermolecular forces in solids are strong, so that the shape and size of solids do not easily change. But this force is less in liquids and gases (together known as fluids) so that their shape is easily changed. If the pressure increases in a solid, based on its inherent properties it experiences tension and ultimately deforms or breaks. In the case of fluids it however causes it to flow rather than to deform. Although liquids and gases share some common characteristics, they have many distinctive characteristics on their own. It is easy to compress a gas whereas liquids are incompressible. Learning of all these facts helps us to understand pressure better. In this lesson you will study about the pressure in fluids, density of fluids and their application in practical life.