What is Capillary action: Definition and 36 Discussions

Capillary action (sometimes capillarity, capillary motion, capillary effect, or wicking) is the process of a liquid flowing in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. The effect can be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube, in porous materials such as paper and plaster, in some non-porous materials such as sand and liquefied carbon fiber, or in a biological cell. It occurs because of intermolecular forces between the liquid and surrounding solid surfaces. If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by cohesion within the liquid) and adhesive forces between the liquid and container wall act to propel the liquid.

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  1. S

    Solving the Problem of Capillary Action in Tiny Peristaltic Pumps

    Hello, I designed a tiny peristaltic pump which works really fine. I am using a very thin tubing of 0.5mm diameter, which makes me struggle with capillary action, unfortunately. When my pump is not working, sometimes liquid still flows into the tubing because of capillary action. Do you have...
  2. Nick tringali

    How does capillary action of a liquid not violate energy conservation?

    I am learning about capillary action of water. As water moves up paper. How is that not violating energy conservation as it is going against the force of gravity. This obviously can't be infinite energy.
  3. T

    Is this a valid way to calculate capillary force / pressure?

    When figuring out the capillary pressure on a liquid in a tube of a certain cross-section, the typical approach is to consider the Young-Laplace pressure and the curvature etc. I was looking through some of my old notes and I had an equation for the capillary force: fc = γ cosθ dS/dx where γ...
  4. B

    Capillary action, evaporative pumping or bio-mechanical pumping....

    I was researching capillary action to design an efficient evaporative cooler, when I found this thread... https://www.physicsforums.com/threads/using-capillary-action-to-raise-water-is-perpetual-flow-possible.551285/ Upon reading this thread, the statement, "Trees are solar driven evaporative...
  5. A

    B Why does mercury rise in a glass capillary tube despite its strong cohesion?

    It's a question which come into my mind after reading related notes now and again and I can't think of plausible response to it. Given Statements: We have a container filled with mercury and a glass capillary tube placed in it . As tube's diameter become smaller mercury's height in tube will get...
  6. D

    Does capillary action use water heat energy?

    Capillary action is a form of work, i.e. an object (water) moved by a force (capillary action) over a distance. Since all work requires energy, what supplies the energy for capillary action? Is the chemical energy of the water increased by adhering to a surface? Perhaps the heat energy of the...
  7. I

    I Capillary Action: Overcoming Capillary Force with Ions

    Hello So like anyone who read about capillary action, you think about free energy generation, but as I read the problem is that the water won't leave the capillary tube on the other side because of the capillary action. So you need to use the capillary force from one end of the tube then...
  8. Alfreds9

    Capillary action speed formula?

    Hi, I was looking for a formula to describe capillary action speed in a medium. On wikipedia (https://en.wikipedia.org/wiki/Capillary_action) I came across a formula which describes the cumulative volume of a liquid drawn by capillary action after time t where V is cumulative volume, A is...
  9. S

    Capillary action at different temperatures

    Hi guys, I'm doing a project at the moment revolving around capillary action and surface tension. Today I conducted an experiment to observe capillary action in a capillary tube and paper towel at different temperatures of water. I don't understand why I've got the following results: As you...
  10. Y

    Capillary Action, Are there structures that aid it?

    Hello, I'm an art student trying to recreate this phenomenon, but maybe on a larger scale. I'm trying to create a sculpture that is able to do that. If I can rely on just structure and not worry about materials, that would be great, since my plan is to be able to 3D print it out of plastic...
  11. M

    Capillary Action Homework: ΔP, γ, R1, R2

    Homework Statement Kindly view the attached. Homework Equations ΔP = γ(1/R1 + 1/R2) The Attempt at a Solution [/B] I've began the topic of fluid mechanics, capillary pressure, surface tension and such and was given this question to try. Now from my limited knowledge it seems to me that in...
  12. L

    Preventing Capillary Action in Hot Chamber Wire Feed-throughs

    I have a strange problem. We test our components in oil in a hot chamber(60-100C). Wires are bought out of the chamber for power supply and data acquisition. The oil from the chamber leaks on to the wires because of heat and capillary action. This makes the wires oily and working with oily wire...
  13. D

    Capillary action with respect to "wicking beds"

    Good day I am interested in making a wicking bed for typical vegetable growing. I have read that the height of the soil should be no higher than 300mm. I suspect this number is experimental or simply copied from other sources. I am a little more curious regarding the mechanics of such a...
  14. A

    Capillary action meniscus height in a tube fitted inside another tube?

    Hello, I was thinking about how would capillary action change in a tube (classic example) and in a tube fitted inside another tube (considering water as the liquid involved). This is no homework question, it's just a thought which striked my mind but I don't have sufficient basic knowledge...
  15. D

    Energy production mechanism using capillary action

    We know that water rises in a glass capillary owing to the surface tension phenomenon. If we make an arrangement as shown in the attachment, (read Water instead of mercury in the attachment, I got confused there) & do the following procedure. The valve at the bottom is open, & the one at the top...
  16. L

    Capillary Action: Comparing B vs D

    How is B more correct than D? Both show that forces between glass and fluid are stronger than those between fluid molecules. Thank you for any insight!
  17. T

    Capillary action with elemental Selenium

    Greetings PFers. I'm designing an experiment that needs to take elemental selenium gas at 500K at 120 PSI to a liquid form at any temp and pressure. I would like to use capillary tubes in conjunction with a pump to convert the gas to a liquid. However, I'm having difficulty finding...
  18. E

    Capillary Action and Young-Laplace

    Hello all. This is my first post and I wasn't exactly sure where to put it, so I apologize if it could be in a better place. Ok... here is my issue. I am currently enrolled in a Surfaces/Interfaces course. Capillary action eludes me. I do not understand WHY capillary action occurs in...
  19. W

    Rise and fall of capillary action

    Assume that I have capillary of radius 0.08 cm. I want to test this capillary for capillary rise action. Formula will be T=hrgρ/2cosθ what will be the rise for water.. ( please tell me the calculated value) And, what will be the fall in mercury. ( How to show it negative as its...
  20. W

    Want to know effect of differnet material on capillary action

    Hey, I need to know the effect ( capillary rise) due to different materials on capillary action. Also, what is the reason behind it, not so complex, just in simple language. It will be more good if I'll get the practical and calculated values of height in capillary tube of different...
  21. M

    Capillary Action: Exploring Very Thin Capillaries

    Considering very thin capillaries, such as found in wood to transport water (~100Micron), I understand that the two main factors in play are gravity and the adhesive forces between the water and the surface of the capillary tube. I understand that gravity is proportional to volume that is...
  22. Y

    Capillary Action and Paper Towel Physics

    Hey guys, I am a little confused with the concept of Capillary actions with specific regards to paper towels. I understand the mechanics behind a single capillary tube and the height that water reaches in relation to surface tension. However, my professor claims that paper towels absorb as...
  23. A

    What causes liquid to rise in a capillary tube?

    This question struck me when i was watching a liquid rise in a capillary tube. I'm curious to know from where the energy gets transferred to the liquid to rise above the surface. Well, one possible explanation that i can think of is air pressure. Though, it can be a possible reason only if the...
  24. J

    Derivation of formula for capillary action

    the height upto which liquid rises in capillary tube is 2S cosθ / ρgR I need a derivation for this - please I know that a combination of adhesive force , surface tension and weight creates the contact angle θ but how to proceed after that? To calculate height h i need to know the force by...
  25. M

    Using capillary action to raise water (Is perpetual flow possible?)

    I know there have been a number of posts relating to capillary action but after reading through them I cannot find an obvious answer to my query. Although capillary action can be used to explain the properties of 'wicking' materials that can raise water vertically I am unsure as to whether it is...
  26. N

    How Does Buoyant Force Influence Water Flow Through a Hole in a Sinking Bowl?

    Homework Statement so i have an to do an EEI for an assignment due this friday. My experiment involves me putting a rounded bowl with a flat bottom and a hole in the center on the bottom onto some still water and testing how the bowl sinks faster as weight is added to the bowl. The water comes...
  27. P

    How does capillary action not violate conservation of energy?

    I know that the law of conservation of energy is not violated by either complete destructive interference or capillary action, but I'm curious then what happens to the energy and where it comes from in these cases, since I can't figure it out. Consider the case of complete destructive...
  28. M

    Can materials with different surface properties move without external forces?

    Ok, let's say you have a short cylinder (about a quarter inch tall and a three inch diameter) now take that cylinder and make one half of the circle hydrophilic and the other half hydrophobic (not the top one way and the bottom the other, I am talking about half the circle like how you would cut...
  29. A

    Capillary action for non-polar substances?

    I thought I understood capillary action, but according to my understanding, non-polar substances shouldn't undergo capillary action. Today in lab, we were working with ether, which is non-polar, and I noticed it climbed up a paper towel. It was slower than water, but still... what intermolecular...
  30. D

    Capillary Action: Exploring Questions & Origins

    I'm not too sure if this is the right board, but it seems the most apt, so here it goes: Question 1: If a column of water rises due to capillary action, its centre of mass must rise too, so where does the energy come from? Question 2: Regarding the origin of capillary action; most...
  31. E

    Using capillary action to generate energy

    Hello. I've had this idea floating around in my head for a long time and lately it's really been bugging me. Say you had a tray of water, and suspended another tray above that, and then you connected the two trays vertically with some very thin tubes, say, 0.2mm in diameter. Now, due to...
  32. L

    Capillary action: mercury depression

    hi guys, need some help for this question. a capillary of unknown internal radius was inserted into a pool of mercury into a pool of mercury. the height of mercury within the capillary was depressed 1.6cm below the free liquid. Calculate the internal diameter of the capillary. For the...
  33. P

    Capillary Action (Capillary Depression)

    Hi, I have questions regarding capillary action and capillary depression for practical purposes. I'm fairly educated in physics and chemistry, but have some "what would happen if..." questions. Please help, and add any information you'd think helpful! 1) Imagine you have your typical...
  34. K

    Capillary Action: Physically Possible Forms

    Homework Statement (see figure) Three forms of capillaries are given, and the question is simple : which of these are physically possible? There are no data given (such as densities or dimensions of the capillaries), so it is just the form that is of importance here. The three cases...
  35. M

    Capillary Action- Rate/Temp- How would you analyze?

    Hi Folks - This started out as a simple experiment we could do for my daughter's science fair (9th grade). Now I am truly ashamed to admit that I don't really know the best way to analyze the reasonably good results of the experiment. The experiment was to measure the effect of fluid...
  36. A

    Surface tension, capillary action, viscous fluid

    I was having trouble with this problem. please let me know how to approach this. thanks. The density of ice is 920 kg/m3, and that of seawater is 1030 kg/m3. What fraction of the total volume of an iceberg is exposed?
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