Name: capillary action in narrow spaces
Uploaded: 2025-02-13T15:43:08.000Z
Duration: 1 min 19 s
Channel: JoVE

تشير الشعيرات الدموية إلى حركة السائل في المساحات الضيقة ، مدفوعة بالتوتر السطحي وقوى الالتصاق بين السائل والأسطح المجاورة.
يتم ملاحظة هذه الحركة بشكل شائع في الأنابيب الرقيقة والمواد المسامية والمساحات الصغيرة الأخرى.
عندما يتم وضع أنبوب ضيق ، يسمى الأنبوب الشعري ، في سائل ، قد يرتفع مستوى السائل أو ينخفض اعتمادا على تفاعل القوى.
عندما تكون القوى اللاصقة بين السائل والأنبوب أقوى من قوى التماسك داخل السائل ، يرتفع السائل ، وهو ما يسمى ارتفاع الشعيرات الدموية.
من ناحية أخرى ، إذا كانت القوى المتماسكة أقوى ، يسقط السائل ، مما يؤدي إلى اكتئاب الشعيرات الدموية.
هناك العديد من العوامل التي تؤثر على الارتفاع الذي يتحرك عنده السائل في أنبوب شعري وهي زاوية التلامس بين الأنبوب والسائل ، والتوتر السطحي للسائل ، وكثافة السائل ، ونصف قطر الأنبوب ، وتأثير الجاذبية.
تعتبر الشعيرات الدموية مهمة في كل من العمليات الطبيعية والتكنولوجيا ، مما يساعد في نقل المياه في النباتات ، وامتصاص السوائل في المواد المسامية ، وتقنيات مثل أجهزة الموائع الدقيقة.

الخاصية الشعيرية في السوائل.

<div style="direction:rtl">تعبر الخاصية الشعيرية عن حركة السوائل في المساحات الضيقة دون تأثير قوى خارجية عليها. تحدث الخاصية الشعيرية بفعل التوتر السطحي وقوى الالتصاق بين السائل والأسطح الصلبة الحاوية له. وغالبًا ما يتم ملاحظة هذا التأثير في الأنابيب الضيقة والمواد المسامية والجسيمات الدقيقة. يمثل التوتر السطحي اهمية بالغة للخاصية الشعيرية. اذ ينتج عن قوى التماسك بين جزيئات السائل عند الحد الفاصل بين السائل والهواء، مما يشكل طبقة رقيقة تقاوم القوى الخارجية.عند وضع الأنبوب الشعري في سائل، يتغير مستوى السائل بناءً على قوى الالتصاق بين السائل وسطح الأنبوب. وإذا كانت قوى الالتصاق هذه أكبر من قوى التماسك بين اجزاء السائل، يرتفع السائل في الأنبوب، وهو ما يُعرف باسم الارتفاع الشعري. وإذا كانت قوى التماسك أقوى، ينخفض ​​مستوى السائل، وهو ما يُعرف باسم الانخفاض الشعري. يتأثر الارتفاع الذي يرتفع إليه السائل أو ينخفض ​​في الأنبوب الشعري بعدة عوامل، تشمل كل من التوتر السطحي للسائل وكثافته، وزاوية التلامس بين السائل والأنبوب، وتأثير الجاذبية، ونصف قطر الأنبوب. تظهر الخاصية الشعيرية في العديد من العمليات الطبيعية والصناعية. فهي تؤثر على حركة الماء والمغذيات في التربة، والذي تمثل اهمية كبيرة لنمو النباتات. وفي المواد المسامية، تؤثر على امتصاص السوائل والاحتفاظ بها. تُستخدم الخاصية الشعيرية أيضًا في تقنيات مثل الطباعة بالحبر النفاث وتقنيات الموائع الدقيقة.</div>

تشير الشعيرات الدموية إلى حركة السائل في المساحات الضيقة ، مدفوعة بالتوتر السطحي وقوى الالتصاق بين السائل والأسطح المجاورة.
هذه...

Education

JoVE Core

Civil Engineering

الهندسة المدنية

Unit 1

الوحدة الأولى

Fluid Properties

خصائص الموائع

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

Capillarity in Fluid

capillary action in narrow spaces

Capillary action is the movement of liquid through narrow spaces without any outside force. It depends on surface tension and adhesion between the liquid and nearby solid surfaces. This effect is common in narrow tubes, porous materials, and fine particles.

Surface tension comes from cohesive forces between liquid molecules at the liquid-air boundary. These forces create a thin skin that resists outside pressure. When a capillary tube is placed in a liquid, the liquid level changes because of its interaction with the tube surface.

If adhesion is stronger than cohesion, the liquid rises in the tube. This is called capillary rise. If cohesion is stronger, the liquid level drops. This is called capillary depression.

The amount a liquid rises or falls depends on several factors. These include surface tension, liquid density, the contact angle with the tube, gravitational acceleration, and the tube radius. Capillarity matters in nature and in technology. It helps move water and nutrients in soil for plant growth, affects liquid absorption and retention in porous materials, and is used in inkjet printing and microfluidics.

Capillary Action in Narrow Spaces

characteristics of fluids

Fluid Behavior in Liquids and Gases

Fluids include liquids and gases, and they behave differently from solids because of how their molecules are arranged. In solids, molecules are tightly packed and held by strong intermolecular forces. That structure helps solids keep their shape and resist deformation. Fluids have molecules that are farther apart and held by weaker forces. Because of this, they can flow and change shape easily. A fluid is any substance that deforms continuously when shearing stress is applied. Shearing stress...

density, specific weight, specific gravity and compressibility of fluid

density-specific-weight-specific-gravity-and-compressibility-of-fluid

Fluid Properties: Density, Weight and Compression

Density, specific weight, specific gravity, and compressibility are key fluid properties. Density is the mass per unit volume of a fluid. It helps describe how much mass a fluid system contains and affects buoyancy, pressure, flow behavior, viscosity, thermal conductivity, and sound propagation. In pipeline design, knowing density helps engineers make sure the pipe can support the fluid’s mass. Specific weight is the weight per unit volume. It is found by multiplying density by gravitational...

viscosity of fluid

How Temperature Changes Fluid Viscosity

Viscosity describes how much a fluid resists flow and deformation. It comes from internal friction between fluid layers that move past each other. Dynamic viscosity, shown by the Greek letter mu (μ), measures the force needed to move one layer over another. Newtonian fluids, such as water and air, have a linear relationship between shearing stress and the rate of shearing strain. Their viscosity stays constant, even when the applied stress changes. Non-Newtonian fluids, like ketchup,...

types of fluids

Newtonian vs Non-Newtonian Fluid Behavior

Fluids can be grouped by how they respond to shear stress. Shear stress is a force that acts across a material, and shear strain rate describes how quickly it changes shape or flows. In this lesson, fluids are divided into Newtonian and non-Newtonian types. Newtonian fluids follow Newton’s law of viscosity. Their shear stress changes in a linear way as the shear rate changes. That means their viscosity stays constant, so their flow is predictable and easier to analyze. Water, air, oil, and...

newtonian fluid: problem solving

Newtonian Fluid Viscosity and Shear Stress

Newtonian fluids have a constant viscosity, so their shear stress and shear strain rate stay directly proportional. This creates a linear, predictable link between force and flow. Water, air, and light oils are common examples of Newtonian fluids. A simple way to study this behavior is to place the fluid between two parallel plates. One plate stays still, and the other moves at a constant velocity. The fluid forms a velocity gradient, which is the change in speed across the distance between...

vapor pressure of fluid

Vapor Pressure and Boiling Behavior

Vapor pressure and boiling behavior are closely linked in fluids. Vapor pressure is the pressure a vapor exerts when it is in thermodynamic equilibrium with its liquid at a given temperature. It shows how strongly molecules tend to leave the liquid surface and move into the vapor phase. A closed container helps show how vapor pressure forms. If a liquid sits in a sealed space with a small air gap, and that space is evacuated, vapor molecules escape from the liquid into the empty space. The...

surface tension of fluid

Why Water Drops and Needles Float

Surface tension helps explain why water forms drops, supports small objects, and moves in thin tubes. It is a property of fluids at the boundary between a liquid and a gas, or between two immiscible liquids. At the surface, molecules are pulled inward by neighboring molecules. That inward pull makes the surface act a little like a stretched elastic membrane. Inside a fluid, molecules are attracted in all directions. Surface molecules do not have the same balance of forces. They feel a net...

capillarity in fluid

Capillary action is the movement of liquid through narrow spaces without any outside force. It depends on surface tension and adhesion between the liquid and nearby solid surfaces. This effect is common in narrow tubes, porous materials, and fine particles. Surface tension comes from cohesive forces between liquid molecules at the liquid-air boundary. These forces create a thin skin that resists outside pressure. When a capillary tube is placed in a liquid, the liquid level changes because of...

design example: deciding thickness of lubricating fluid in a shaft

design-example-deciding-thickness-of-lubricating-fluid-in-a-shaft

Lubricant Film Thickness for Shaft Bearings

Lubricant film thickness for shaft bearings is calculated to keep a rotating shaft from touching its bearing housing. A controlled layer of lubricant reduces friction, wear, and energy loss. It also helps the machine run smoothly by preventing metal-to-metal contact. The calculation starts with the shaft’s tangential velocity. First, the rotational speed is converted to angular velocity. Then that value is multiplied by the shaft radius. The result is the shaft’s linear speed at its surface...

key terms and concepts

Learn how capillary action moves liquid through narrow spaces using surface tension and adhesion, and see its role in plants, porous materials, and printing.

Capillary Action in Narrow Spaces | JoVE K12

JoVE Core Civil Engineering provides a foundational exploration of essential construction materials in civil engineering, focusing on bricks, stones, steel, wood, and concrete through easy-to-understand animated videos. This collection covers the properties, manufacturing processes, and practical applications of these materials. Additionally, the accompanied science-in-action videos demonstrate the research experiments performed in laboratories.

civil engineering

Capillary Action in Narrow Spaces

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