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

Kapilarność odnosi się do ruchu cieczy w wąskich przestrzeniach, napędzanego napięciem powierzchniowym i siłami adhezyjnymi między cieczą a pobliskimi powierzchniami.
Taki ruch jest powszechnie obserwowany w cienkich rurkach, porowatych materiałach i innych małych przestrzeniach.
Kiedy wąska rurka, zwana rurką kapilarną, jest umieszczana w cieczy, poziom cieczy może się podnieść lub spaść w zależności od interakcji sił.
Kiedy siły adhezyjne między cieczą a rurką są silniejsze niż siły kohezyjne w cieczy, ciecz unosi się, co nazywa się wzrostem kapilarnym.
Z drugiej strony, jeśli siły kohezyjne są silniejsze, ciecz opada, powodując zagłębienie kapilarne.
Kilka czynników wpływających na wysokość, na której ciecz porusza się w rurce kapilarnej, to kąt zwilżania między rurką a cieczą, napięcie powierzchniowe cieczy, gęstość cieczy, promień rurki i wpływ grawitacji.
Kapilarność jest ważna zarówno w procesach naturalnych, jak i technologii, pomagając w transporcie wody w roślinach, absorpcji cieczy w materiałach porowatych i technologiach takich jak urządzenia mikroprzepływowe.

kapilary w cieczy

Kapilara opisuje ruch cieczy w małych przestrzeniach bez oddziaływania na nią sił zewnętrznych. Jest to zjawisko napędzane napięciem powierzchniowym oraz oddziaływaniami adhezyjnymi między cieczą a otaczającymi ją powierzchniami stałymi. Efekt ten jest często obserwowany w wąskich rurkach, materiałach porowatych i drobnych cząsteczkach.

Napięcie powierzchniowe ma kluczowe znaczenie dla kapilarności. Wynika ono z sił spójności między cząsteczkami cieczy na granicy ciecz-powietrze, tworząc powłokę, która opiera się siłom zewnętrznym. Gdy rurka kapilarna zostaje umieszczona w cieczy, poziom cieczy zmienia się w zależności od oddziaływań adhezyjnych między cieczą a powierzchnią rurki. Jeśli siły adhezyjne są większe od sił spójności cieczy, ciecz wznosi się w rurce, co jest znane jako podnoszenie kapilarne. Jeśli siły spójności są silniejsze, poziom cieczy opada, co nazywane jest obniżeniem kapilarnym.

Wysokość, na jaką ciecz wznosi się lub opada w rurce kapilarnej, zależy od kilku czynników, w tym napięcia powierzchniowego i gęstości cieczy, kąta zwilżenia między cieczą a rurką, przyspieszenia grawitacyjnego oraz promienia rurki.

Kapilarność bierze udział w wielu procesach naturalnych i przemysłowych. Wpływa na ruch wody glebowej oraz składników odżywczych, co jest niezbędne do wzrostu roślin. W materiałach porowatych ma wpływ na absorpcję i retencję cieczy. Kapilarność jest również wykorzystywana w technologiach takich jak druk atramentowy i mikroprzepływy.

Kapilary w cieczy

Kapilarność odnosi się do ruchu cieczy w wąskich przestrzeniach, napędzanego napięciem powierzchniowym i siłami adhezyjnymi między cieczą a pobliskimi powierzchniami.
Taki...

Education

JoVE Core

Civil Engineering

Inżynieria lądowa

Unit 1

Jednostka 1

Fluid Properties

Właściwości płynów

KEY TERMS AND CONCEPTS

KLUCZOWE TERMINY I POJĘCIA

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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