Name: pascal’s principle in static fluids
Uploaded: 2023-04-30T11:04:20.000Z
Duration: 1 min 4 s
Channel: JoVE

K12 Standards

Alabama Course of Study Science

9-12

Physics

motion-and-stability-forces-and-interactions

Motion and Stability: Forces and Interactions

9-12.P.1.4.b

Pascal's Law

El principio de Pascal establece que si se cambia la presión en un fluido confinado, el cambio se transmite a todo el fluido y a las paredes del recipiente sin disminuir en magnitud.
Para comprender este principio, considere una pistola de agua de boquilla múltiple de área de sección transversal A llena de agua.
Cuando el pistón se presiona con una fuerza F, el cambio de presión correspondiente F/A se transmite a través de todo el volumen de agua y llega a cada boquilla.
El agua se libera con la misma presión a través de cada boquilla, siguiendo el principio de Pascal.
Tomando otro ejemplo, supongamos que un barril está conectado a una tubería larga y delgada a través de la cual se vierte el agua.
Cuando el barril está lleno y se vierte una cantidad adicional de agua en él, la presión ejercida por el agua que ingresa aumenta rápidamente en todo su volumen en el barril, lo que hace que gotee por todos lados.

ley de pascal

En 1653, el filósofo y científico francés Blaise Pascal publicó "Tratado sobre el equilibrio de los líquidos", en el que se discuten los principios de los fluidos estáticos. Un fluido estático es un fluido que no está en movimiento. Cuando un fluido no fluye, decimos que el fluido está en equilibrio estático. Si el fluido es agua, decimos que está en equilibrio hidrostático. Para un fluido en equilibrio estático, la fuerza neta en cualquier parte del fluido debe ser cero; de lo contrario, el fluido comenzará a fluir. Pascal observó que un cambio en la presión aplicada a un fluido encerrado se transmite sin disminución a lo largo del fluido y a las paredes de su recipiente. Además, el principio de Pascal implica que la presión total en un fluido es la suma de las presiones de diferentes fuentes. Por ejemplo, la presión a cierta profundidad en un fluido depende de la profundidad del fluido y la presión atmosférica. En un fluido encerrado, dado que los átomos del fluido pueden moverse libremente, transmiten presión a todas las partes del fluido y a las paredes del recipiente. Cualquier cambio en la presión se transmite sin disminución. Hay que tener en cuenta que este principio no afirma que la presión sea la misma en todos los puntos de un fluido, lo que no es cierto, ya que la presión en un fluido cerca de la Tierra varía con la altura. Mas bien, este principio se aplica al cambio en presión. Supongamos que se agrega agua en un recipiente cilíndrico de altura (H) y área de sección transversal (A) que tiene un pistón móvil de masa m. Agregar peso (mg) en la parte superior del pistón aumenta la presión en la parte superior por mg/A, ya que el peso adicional también actúa sobre el área (A) de la tapa. De acuerdo con el principio de Pascal, la presión en todos los puntos del agua cambia en la misma magnitud, mg/A. Por lo tanto, la presión en el fondo también aumenta en mg/A. Así, la presión en el fondo del recipiente es igual a la suma de la presión atmosférica, la presión debida al fluido y la presión suministrada por la masa. Este texto está adaptado de<a href="https://openstax.org/books/university-physics-volume-1/pages/14-3-pascals-principle-and-hydraulics"> Openstax, University Physics Volume 1, Sección 14.3: Principio de Pascal y la hidráulica.</a>

Ley de Pascal

En 1653, el filósofo y científico francés Blaise Pascal publicó "Tratado sobre el equilibrio de los líquidos", en el que se analizaba el ...

Education

Educación

JoVE Core

Física

Unit 1

Unidad 1

Fluid Mechanics

Mecánica de fluidos

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

pascal’s principle in static fluids

Pascal’s principle explains how pressure changes move through a fluid that is not flowing. A fluid at rest is in static equilibrium. If the fluid is water, it is in hydrostatic equilibrium. In this state, the net force on any part of the fluid must be zero, or the fluid will begin to flow.

Blaise Pascal described this idea in 1653 in Treatise on the Equilibrium of Liquids. He showed that when pressure changes in an enclosed fluid, that change is transmitted without loss through the fluid and to the walls of the container. The principle applies to pressure changes, not to the total pressure being the same everywhere. In fluid near Earth, pressure still varies with height.

The total pressure in a fluid can come from more than one source. At a certain depth, pressure depends on the fluid depth and the pressure of the atmosphere. Inside an enclosed fluid, the moving atoms pass pressure along to all parts of the fluid and to the container walls. That is why any added pressure spreads undiminished.

A simple piston example shows this clearly. Imagine water in a cylindrical container with height H and cross-sectional area A, and a movable piston of mass m. If an extra weight of mg is placed on the piston, the pressure at the top increases by mg/A because the weight acts over area A. Pascal’s principle says the pressure throughout the water changes by the same amount, so the bottom pressure also rises by mg/A. The pressure at the bottom is then the sum of atmospheric pressure, fluid pressure, and the pressure from the added mass.

Pascal’s Principle in Static Fluids

characteristics of fluids

Fluid Behavior Under Force

Fluid behavior under force differs from the behavior of solids. When a force acts parallel to the top surface of a solid, the solid resists it because of internal friction between its layers. This is called shearing resistance. If the force is removed, the shearing forces help the solid return to its original shape. Other deformation forces can also change the shape of a solid for a short time, as long as the force stays below a threshold magnitude. Solids usually keep their shape, which makes...

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density

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pressure of fluids

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variation of atmospheric pressure

Atmospheric Pressure and Altitude

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pascal's law

Pascal’s principle explains how pressure changes move through a fluid that is not flowing. A fluid at rest is in static equilibrium. If the fluid is water, it is in hydrostatic equilibrium. In this state, the net force on any part of the fluid must be zero, or the fluid will begin to flow. Blaise Pascal described this idea in 1653 in Treatise on the Equilibrium of Liquids. He showed that when pressure changes in an enclosed fluid, that change is transmitted without loss through the fluid and...

application of pascal's law

Hydraulic Force Transfer with Pascal's Law

Hydraulic force transfer uses Pascal's law to move pressure through an enclosed fluid. Pascal showed experimentally that a change in pressure applied to a confined fluid is transmitted undiminished throughout the fluid and to the walls of its container. That idea is the basis of hydraulics, a major part of modern mechanical technology. Hydraulic systems appear in automotive brakes, hydraulic jacks, and many other machines. A simple hydraulic system uses two pistons at the same height. Because...

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archimedes' principle

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density and archimedes' principle

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accelerating fluids

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buoyancy

Buoyant Force in Sinking and Floating

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contact angle

Wetting and Surface Curvature

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rise of liquid in a capillary tube

Capillary Action in Thin Tubes

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bernoulli's equation

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bernoulli's principle

Fluid Pressure and Speed Changes

Bernoulli's equation links fluid pressure and fluid speed in a static, incompressible fluid. For horizontal flow, where gravitational energy density stays constant, the equation is especially useful. In that setting, the result is known as Bernoulli's principle. Bernoulli's principle says that fluid pressure drops when speed increases, and pressure rises when speed decreases. This pressure-speed relationship helps explain how moving fluids behave in simple flow situations. It also provides a...

bernoulli's principle: applications

Bernoulli's Principle in Fluid Devices

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energy conservation and bernoulli's equation

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Bernoulli’s Equation in Streamlined Flow

Bernoulli’s equation describes energy in a moving fluid. It comes from the conservation of energy principle, or the work-energy theorem, applied to an incompressible, inviscid fluid in laminar, steady, irrotational flow. The equation says that pressure energy, potential energy, and kinetic energy per unit volume stay constant along a streamline. Each term has the units of energy per unit volume. The kinetic energy per unit volume is called kinetic energy density, and the potential energy per...

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viscosity

Viscosity and How Fluids Flow

Viscosity describes how easily a fluid flows. Water moves quickly, while honey and maple syrup flow slowly and stick to a surface. That difference comes from fluid friction between liquid layers and between a fluid and the material around it. In this example, water has a lower viscosity than honey and maple syrup. Viscosity is measured in newton-second per meter squared (N·s/m2) or pascal-second (Pa·s). It also changes with temperature and can differ from one fluid to another by several orders...

poiseuille's law and reynolds number

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stokes' law

Terminal Velocity in a Viscous Fluid

Viscous forces act like friction in a liquid. They resist the relative motion of molecules and pull back on a solid body moving through the fluid. The size of this force depends on the body’s shape and size, its speed, and the liquid’s viscosity, density, and temperature. For a spherical solid object, the force in a fluid is described by Stokes’ law. This law applies only at low Reynolds number, when the flow is laminar and not turbulent. Experiments show that the force is proportional to the...

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key terms and concepts

Learn how pressure changes move through static fluids, why pressure is added in enclosed liquids, and how a piston changes pressure in water.

Pascal’s Principle in Static Fluids | JoVE K12

physics

JoVE Core Física presenta la teoría y la aplicación de conceptos físicos fundamentales, como la cinemática, dinámica, mecánica de fluidos, estática, ondas y acústica, mediante animaciones audiovisuales concisas y fáciles de entender. Además, los vídeos de científicos en acción muestran la aplicación de los conceptos relacionados en experimentos de investigación clásicos y originales, realizados en laboratorios de todo el mundo.

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Pascal’s Principle in Static Fluids

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