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

모세관(capillarity)은 좁은 공간에서 액체의 이동을 말하며, 액체와 주변 표면 사이의 표면 장력과 접착력에 의해 구동됩니다.
이러한 움직임은 얇은 튜브, 다공성 재료 및 기타 작은 공간에서 일반적으로 관찰됩니다.
모세관 튜브라고 하는 좁은 튜브를 액체에 넣으면 힘의 상호 작용에 따라 액체 레벨이 오르거나 내릴 수 있습니다.
액체와 튜브 사이의 접착력이 액체 내의 응집력보다 강하면 액체가 상승하며이를 모세관 상승이라고 합니다.
반면에 응집력이 더 강하면 액체가 떨어져 모세관 함몰이 발생합니다.
모세관에서 액체가 이동하는 높이에 영향을 미치는 몇 가지 요인은 튜브와 액체 사이의 접촉각, 액체의 표면 장력, 액체의 밀도, 튜브의 반경 및 중력의 영향입니다.
모세관은 자연적 과정과 기술 모두에서 중요하며, 식물의 수분 수송, 다공성 물질의 액체 흡수 및 미세 유체 장치와 같은 기술을 돕습니다.

유체의 모세관 현상

Capillarity in Fluid

모세관 현상은 외부 힘이 작용하지 않는 작은 공간에서 액체가 움직이는 현상을 설명합니다. 모세관 현상은 액체와 주변 고체 표면 사이의 표면 장력과 접착 상호 작용에 의해 발생합니다. 이 효과는 좁은 관, 다공성 재료 및 미세 입자에서 자주 나타납니다.

표면 장력은 모세관 현상에 중요합니다. 이는 액체-공기 경계에서 액체 분자 간의 응집력으로 인해 발생하여 외부 힘에 저항하는 피부를 형성합니다. 모세관을 액체에 놓으면 액체와 관 표면 사이의 접착 상호 작용에 따라 액체 수위가 변합니다. 이러한 접착력이 액체의 응집력보다 크면 관에서 액체가 올라가는데, 이를 모세관 상승이라고 합니다. 응집력이 더 강하면 액체 수위가 내려가는데, 이를 모세관 저하라고 합니다.

모세관에서 액체가 올라가거나 내려가는 높이는 액체의 표면 장력과 밀도, 액체와 관 사이의 접촉각, 중력 가속도, 관의 반경을 포함한 여러 요인의 영향을 받습니다.

모세관 현상은 많은 자연 및 산업 공정에 관여합니다. 토양 수분과 영양소 이동에 영향을 미치며, 이는 식물 성장에 필수적입니다. 다공성 재료에서는 액체 흡수 및 유지에 영향을 미칩니다. 모세관 현상은 잉크젯 인쇄 및 마이크로유체와 같은 기술에도 사용됩니다.

모세관(capillarity)은 좁은 공간에서 액체의 이동을 말하며, 액체와 주변 표면 사이의 표면 장력과 접착력에 의해 구동됩니다.
이러한...

Education

JoVE Core

Civil Engineering

Unit 1

Fluid Properties

KEY TERMS AND CONCEPTS

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 offers a foundational exploration of essential construction materials such as bricks, stones, steel, wood, and concrete, along with fluid mechanics topics like flow over immersed bodies, open channel flow, and dimensional modeling. It also covers key surveying concepts, including leveling, traverse adjustments, curve design, topographic mapping, and geospatial technologies (GPS & GIS). Science-in-action videos showcase laboratory research on materials, fluids, and surveying practices in real-world engineering systems.

civil engineering

Capillary Action in Narrow Spaces

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