Understanding Fluid Pressure, States of Matter, and Buoyancy

Fluid Pressure and its Effects

A fluid exerts pressure in all directions on a body immersed in it (P = d * h * g). The magnitude increases with depth. The pressure does not depend on the area. If h is the same, the pressure will be the same. But the force depends on the area. The force of the water at the bottom of a lake is greater than that exerted in a pool (F = P * A). The pressure exerted by a liquid also depends on its density. If the liquid in Torricelli's experiment had been any other than mercury and of lower density, the column would have increased.

Bathysphere: A spherical steel tank used for underwater observations, supported by a cable from a ship.

States of Matter

• Solid: Molecules are linked by very strong cohesion and have a definite volume. It operates at normal temperatures.
• Liquid: Molecules are separated, its cohesive force is weak, it has volume, but its shape depends on the container. It operates at normal temperatures.
• Gaseous: Molecules are far apart and its cohesive force is very weak, has no form or volume, takes the shape of the container. It operates at normal temperatures.
• Plasma: Electrons are separated from the protons in the atomic nucleus, runs at high temperatures, there is no cohesive force and is called ion plasma because the electric charges are moving independently.
• Bose-Einstein Condensate (BEC): The material is condensed into a super atom, runs at close to absolute zero temperatures and the atoms are in their ground state.

Strong Cohesion Forces

Forces exerted by the atoms among themselves to form different molecules. Follows the interactions that occur between electrons and protons of different atoms.

Buoyancy and Archimedes' Principle

Thrust: A force with which a fluid acts vertically upwards on any body immersed in whole or in part. The thrust exists because the liquid pressure in the lower body is greater than the top (E = Vc * Pf) (Volume * Specific Gravity) N, Di Kg.

Pascal's Principle

Solids transmit forces only in the direction in which they are implemented, while fluids transmit pressure in all directions. (This can be verified when inflating a rubber balloon). Any pressure exerted on a fluid in equilibrium is transmitted entirely in all directions. This principle applies to hydraulic brakes, hydraulic elevators, and hydraulic presses.

Specific Gravity

The specific gravity of a substance is the ratio between the weight of any portion of this material and its corresponding volume (P = p / V) (P = d * g) Kg/dm3; N/m3; gr/cm3 (Specific gravity is the material weight per unit volume and density is the mass per unit volume).

Application of Archimedes' Principle

Condition of floating bodies: A body immersed in a liquid is faced with two opposing forces, weight and thrust.

• If E < p, the body sinks.
• If E = p, the body remains in suspension.
• If E > p, the body floats on the surface.

"Every body that floats on the surface of a liquid, its weight equals the weight of the liquid displaced by the submerged part."

A body of greater specific gravity than water can float if the body is given a special shape that allows it to displace a volume of water whose weight equals the weight of the body.

Examples of Plasmas

• Artificially Produced: Fluorescent tubes, rockets, electric shock, plasma balls.
• Earth Plasmas: Fire, lightning, ionosphere, aurora lights.
• Space Plasmas and Astrophysics: Stars (sun), solar wind, interplanetary medium and intergalactic medium, accretion disks and intergalactic nebulae.

Dilation

Bodies expand when heated and contract when their temperature is reduced. It is divided into:

• Linear expansion: Increase in length (wire rods, rails, rods, etc.).
• Superficial dilation: Increase in area (windows, tiles, rings, etc.).
• Volume expansion: Increase in volume (spheres, cubes, prisms, etc.).