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

毛細管現象とは、狭い空間での液体の動きを指し、液体と近くの表面との間の表面張力と接着力によって駆動されます。
このような動きは、細いチューブ、多孔質材料、およびその他の小さなスペースで一般的に観察されます。
キャピラリーチューブと呼ばれる細いチューブを液体に入れると、力の相互作用によって液面が上下することがあります。
液体とチューブの間の接着力が液体内の凝集力よりも強い場合、液体は上昇し、これを毛細管上昇と呼びます。
一方、凝集力が強いと液体が落ちてしまい、毛細管の陥凹が生じます。
キャピラリーチューブ内で液体が移動する高さに影響を与えるいくつかの要因は、チューブと液体の間の接触角度、液体の表面張力、液体の密度、チューブの半径、および重力の影響です。
毛細管現象は、植物の水輸送、多孔質材料での液体吸収、マイクロ流体デバイスなどの技術など、自然のプロセスと技術の両方で重要です。

流体の毛細管現象

毛細管現象とは、外部からの力が作用していない狭い空間での液体の動きを指します。毛細管現象は、表面張力と、液体と周囲の固体表面との間の接着相互作用によって発生します。この効果は、細い管、多孔質材料、微粒子でよく見られます。

 毛細管現象にとって表面張力は重要です。これは、液体と空気の境界にある液体分子間の凝集力によって生じ、外部からの力に抵抗する皮膜を形成します。毛細管を液体内に置くと、液体と管表面との間の接着相互作用に基づいて液面が変化します。これらの接着力が液体の凝集力よりも大きい場合、液体は管内で上昇します。これを毛細管上昇と呼びます。凝集力がより強い場合、液面は下降します。これを毛細管下降と呼びます。

 毛細管内で液体が上昇または下降する高さは、液体の表面張力と密度、液体と管の接触角、重力加速度、管の半径など、いくつかの要因によって左右されます。

 毛細管現象は、多くの自然および産業プロセスに関係しています。毛細管現象は、植物の成長に不可欠な土壌水分と栄養素の移動に影響します。多孔質材料では、液体の吸収と保持に影響します。毛細管現象は、インクジェット印刷やマイクロ流体工学などの技術にも使用されています。

毛細管現象とは、狭い空間での液体の動きを指し、液体と近くの表面との間の表面張力と接着力によって駆動されます。
そういう。。。

Education

JoVE Core

Civil Engineering

土木工学

Unit 1

ユニット1

Fluid Properties

流体の特性

KEY TERMS AND CONCEPTS

主要用語と概念

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

Description

Transcript