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

A capilaridade refere-se ao movimento do líquido em espaços estreitos, impulsionado pela tensão superficial e forças adesivas entre o líquido e as superfícies próximas.
Esse movimento é comumente observado em tubos finos, materiais porosos e outros espaços pequenos.
Quando um tubo estreito, chamado tubo capilar, é colocado em um líquido, o nível do líquido pode subir ou descer dependendo da interação das forças.
Quando as forças adesivas entre o líquido e o tubo são mais fortes do que as forças coesivas dentro do líquido, o líquido sobe, o que é chamado de aumento capilar.
Por outro lado, se as forças coesivas forem mais fortes, o líquido cai, resultando em depressão capilar.
Vários fatores que influenciam a altura em que o líquido se move em um tubo capilar são o ângulo de contato entre o tubo e o líquido, a tensão superficial do líquido, a densidade do líquido, o raio do tubo e o efeito da gravidade.
A capilaridade é importante tanto nos processos naturais quanto na tecnologia, auxiliando no transporte de água nas plantas, na absorção de líquidos em materiais porosos e em tecnologias como dispositivos microfluídicos.

capilaridade em fluido

A capilaridade descreve o movimento do líquido em pequenos espaços sem forças externas atuando sobre ele. A capilaridade é impulsionada pela tensão superficial e interações adesivas entre o líquido e as superfícies sólidas circundantes. Esse efeito é frequentemente visto em tubos estreitos, materiais porosos e partículas finas.

A tensão superficial é crucial para a capilaridade. Ela resulta de forças coesivas entre moléculas líquidas na fronteira líquido-ar, formando uma pele que resiste a forças externas. Quando o tubo capilar é colocado em um líquido, o nível do líquido muda com base nas interações adesivas entre o líquido e a superfície do tubo. Se essas forças adesivas forem maiores do que as forças coesivas do líquido, o líquido sobe no tubo, conhecido como ascensão capilar. Se as forças coesivas forem mais fortes, o nível do líquido cai, conhecido como depressão capilar.

A altura em que o líquido sobe ou desce em um tubo capilar é influenciada por vários fatores, incluindo a tensão superficial e a densidade do líquido, o ângulo de contato entre líquido e o tubo, aceleração gravitacional e o raio do tubo.

A capilaridade está envolvida em muitos processos naturais e industriais. Ela afeta a água do solo e o movimento de nutrientes, o que é essencial para o crescimento das plantas. Em materiais porosos, ela impacta a absorção e retenção de líquidos. A capilaridade também é usada em tecnologias como impressão a jato de tinta e microfluídica.

Capilaridade em Fluido

A capilaridade refere-se ao movimento do líquido em espaços estreitos, impulsionado pela tensão superficial e forças adesivas entre o líquido e as superfícies próximas.
Tal...

Education

JoVE Core

Civil Engineering

Engenharia Civil

Unit 1

Unidade 1

Fluid Properties

Propriedades dos Fluidos

KEY TERMS AND CONCEPTS

TERMOS E CONCEITOS-CHAVE

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

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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

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viscosity of fluid

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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

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newtonian fluid: problem solving

Newtonian Fluid Viscosity and Shear Stress

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vapor pressure of fluid

Vapor Pressure and Boiling Behavior

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surface tension of fluid

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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

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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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