Definition: Positive hydrostatic pressure is the pressure exerted by a fluid on an object placed in it, which is perpendicular to the surface of the object. This pressure is greater at the deeper levels of the fluid due to the weight of the fluid above it.

Causes: Positive hydrostatic pressure is caused by the weight of the fluid above an object, and it increases with increasing depth of the fluid. The pressure is directly proportional to the density of the fluid and the depth of the object below the surface.

Effects: Positive hydrostatic pressure has several effects on objects placed in a fluid, including:

- Buoyancy: Positive hydrostatic pressure creates an upward force on an object, which is known as buoyancy. This force is equal to the weight of the fluid displaced by the object.

- Compression: Objects placed in a fluid can experience compression due to the pressure exerted by the fluid. This can lead to changes in the shape and size of the object.

- Fluid flow: Positive hydrostatic pressure can cause fluid to flow around an object, leading to drag or lift forces.

Applications: Positive hydrostatic pressure has several important applications in everyday life, including:

- Water distribution: Positive hydrostatic pressure is used to distribute water to homes and businesses through pipes.

- Diving: Divers must take into account the positive hydrostatic pressure they experience as they descend into the water, which can cause compression and affect their buoyancy.

- Hydraulic systems: Positive hydrostatic pressure is used in hydraulic systems to transmit force and power.

In summary, positive hydrostatic pressure is the pressure exerted by a fluid on an object placed in it. It is caused by the weight of the fluid above the object and increases with increasing depth. Positive hydrostatic pressure has several effects on objects, including buoyancy, compression, and fluid flow, and it has important applications in areas such as water distribution, diving, and hydraulic systems.

Movement of water toward gravity is known as positive hydrostatic pressure..Positive hydrostatic pressure is responsible for movement through phloem. It works like garden hose , in which also water moves from high pressure site to lower pressure site. In plants, the leaves ( source) have large amount of stored food in the form of sugar . Active transport of solute molecules occurs into sieve-tube element. As a result, water moves from neighbouring cells into the sieve-tube element by osmosis,. This increases hydrostatic pressure , that pushes the sap down the phloem tube.On reaching the sugar sinks, opposite to source site happens.