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

Pascal ilkesi, kapalı bir sıvıdaki basınç değiştirilirse, değişikliğin büyüklükte azalmadan tüm sıvıya ve kabın duvarlarına iletildiğini belirtir.
Bu prensibi anlamak için, suyla doldurulmuş kesit alanı A'nın çok nozullu bir su tabancasını düşünün.
Pistona bir F kuvveti ile basıldığında, karşılık gelen basınç değişimi F/A tüm su hacmi boyunca iletilir ve her bir nozüle ulaşır.
Su, Pascal prensibine göre her nozuldan aynı basınçla serbest bırakılır.
Başka bir örnek alarak, bir namlunun suyun döküldüğü uzun ince bir boruya bağlanmasına izin verin.
Namlu dolduğunda ve içine ilave bir miktar su döküldüğünde, giren suyun uyguladığı basınç, namlu içindeki hacmi boyunca hızla artar ve her taraftan sızmasına neden olur.

pascal'ın yasası

1653 yılında, Fransız filozof ve bilim adamı Blaise Pascal "Treatise on the Equilibrium of Liquids" adlı eseri yayımladı ve bu eserde statik sıvıların prensiplerini ele aldı. Statik bir sıvı, hareket halinde olmayan bir sıvıdır. Bir sıvı akış yapmadığında, sıvının statik denge durumunda olduğunu söyleriz. Eğer sıvı su ise, bunun hidrostatik denge durumunda olduğunu söyleriz. Statik denge durumundaki bir sıvıda, sıvının herhangi bir bölümüne etki eden net kuvvet sıfır olmalıdır; aksi halde sıvı akışmaya başlar. Pascal, kapalı bir sıvıya uygulanan basınçta meydana gelen bir değişikliğin, sıvı boyunca ve kapının duvarlarına azaltılmamış şekilde iletimini gözlemledi. Dahası, Pascal'ın prensibi, bir sıvıdaki toplam basıncın farklı kaynaklardan gelen basınçların toplamı olduğunu ima eder. Örneğin, bir sıvıdaki belirli bir derinlikteki basınç, sıvının derinliğine ve atmosfer basıncına bağlıdır.

Kapalı bir sıvıda, sıvının atomları serbestçe hareket edebildiği için, basıncı sıvının tüm parçalarına ve kapının duvarlarına iletip. Basınçtaki bir değişiklik azaltılmamış şekilde iletildi. Bu ilkenin, sıvının tüm noktalarında basıncın aynı olduğunu söylemediğine dikkat edin - ki bu doğru değildir, çünkü yeryüzü yakınındaki bir sıvıdaki basınç yükseklikle değişir. Bunun yerine, bu ilke basınç değişimine uygulanır. Bir silindirik bir kap içine (H) ve kesit alanı (A) eklendiğinde su miktarı, hareketli bir pistonun kütle m'si olan ağırlık (mg) pistonun üstünden eklenir ve çünkü ek ağırlık da aynı şekilde kapağın alanı (A) üzerinde etki yapar, üstteki basınç mg / A ile artar.

Pascal'ın prensibine göre, suyun tüm noktalarındaki basınç aynı miktarda mg / A değişir. Dolayısıyla, tabanındaki basınç da mg / A ile artar. Bu nedenle, kapının altındaki basınç, atmosfer basıncının, sıvının basıncının ve kütlenin sağladığı basıncın toplamına eşittir.

Bu metin, <a href="https://openstax.org/books/university-physics-volume-1/pages/14-3-pascals-principle-and-hydraulics">Openstax, University Physics Volume 1, Section 14.3: Pascal'ın Prensibi ve Hidrolik adlı kaynaktan uyarlanmıştır.</a>

Pascal'ın Yasası

1653'te Fransız filozof ve bilim adamı Blaise Pascal, "Sıvıların Dengesi Üzerine İnceleme" yi yayınladı.

Education

JoVE Core

Fizik

Unit 1

Ünite 1

Fluid Mechanics

Akışkanlar Mekaniği

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

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

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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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density and archimedes' principle

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excess pressure inside a drop and a bubble

excess-pressure-inside-a-drop-and-a-bubble

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buoyancy

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contact angle

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rise of liquid in a capillary tube

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Capillary action explains why liquid can rise or fall in a very thin tube compared with the liquid around it. A capillary is a narrow cylindrical tube, and the effect becomes noticeable when it is dipped into a liquid. The movement happens because two forces act in opposite directions. Cohesive forces make liquid molecules stick to each other, so the liquid tends to hold together and form a rounded shape. Adhesive forces pull the liquid toward the walls of the container. In a narrow glass...

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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

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energy conservation and bernoulli's equation

energy-conservation-and-bernoulli-s-equation

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

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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

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Pascal’s Principle in Static Fluids

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