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

La capillarité fait référence au mouvement du liquide dans des espaces étroits, entraîné par la tension superficielle et les forces d’adhérence entre le liquide et les surfaces voisines.
Un tel mouvement est couramment observé dans les tubes minces, les matériaux poreux et autres petits espaces.
Lorsqu’un tube étroit, appelé tube capillaire, est placé dans un liquide, le niveau du liquide peut augmenter ou diminuer en fonction de l’interaction des forces.
Lorsque les forces d’adhérence entre le liquide et le tube sont plus fortes que les forces de cohésion à l’intérieur du liquide, le liquide monte, ce qu’on appelle la montée capillaire.
D’autre part, si les forces de cohésion sont plus fortes, le liquide tombe, ce qui entraîne une dépression capillaire.
Plusieurs facteurs qui influencent la hauteur à laquelle le liquide se déplace dans un tube capillaire sont l'angle de contact entre le tube et le liquide, la tension superficielle du liquide, la densité du liquide, le rayon du tube et l'effet de la gravité.
La capillarité est importante à la fois dans les processus naturels et la technologie, car elle facilite le transport de l’eau dans les plantes, l’absorption de liquide dans les matériaux poreux et les technologies telles que les dispositifs microfluidiques.

capillarité dans les fluides

La capillarité décrit le mouvement d'un liquide dans de petits espaces sans que des forces externes n'agissent sur lui. La capillarité est entraînée par la tension superficielle et les interactions adhésives entre le liquide et les surfaces solides environnantes. Cet effet est souvent observé dans les tubes étroits, les matériaux poreux et les particules fines.

La tension superficielle est essentielle à la capillarité. Elle résulte des forces de cohésion entre les molécules liquides à la limite liquide-air, formant une peau qui résiste aux forces externes. Lorsque le tube capillaire est placé dans un liquide, le niveau du liquide change en fonction des interactions adhésives entre le liquide et la surface du tube. Si ces forces adhésives sont supérieures aux forces de cohésion du liquide, le liquide monte dans le tube, ce qu'on appelle la montée capillaire. Si les forces de cohésion sont plus fortes, le niveau du liquide baisse, ce qu'on appelle la dépression capillaire.

La hauteur à laquelle le liquide monte ou descend dans un tube capillaire est influencée par plusieurs facteurs, notamment la tension superficielle et la densité du liquide, l'angle de contact entre le liquide et le tube, l'accélération gravitationnelle et le rayon du tube.

La capillarité intervient dans de nombreux processus naturels et industriels. Elle affecte le mouvement de l'eau et des nutriments dans le sol, ce qui est essentiel à la croissance des plantes. Dans les matériaux poreux, elle affecte l'absorption et la rétention des liquides. La capillarité est également utilisée dans des technologies telles que l'impression à jet d'encre et la microfluidique.

Capillarité dans les fluides

La capillarité fait référence au mouvement du liquide dans des espaces étroits, entraîné par la tension superficielle et les forces d’adhérence entre le liquide et les surfaces voisines.
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Education

Enseignement

JoVE Core

Civil Engineering

Génie civil

Unit 1

Unité 1

Fluid Properties

Propriétés des fluides

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

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

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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...

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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.

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civil engineering

Capillary Action in Narrow Spaces

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