Recent content by Medicago

  1. M

    Can Branching Capillary Increase Water Height?

    I asked some faculty members (mechanical engineering) and no-one gave me a straight answer, but nobody said it was not valid. Also I found it being used in an article but without explanation or reference so I guess it's trivial. Anyway if anyone has any other ideas, I'd love to hear. thanks
  2. M

    Can Branching Capillary Increase Water Height?

    A pressure jump at the meniscus causes a force at the surface. It exists only at the surface, not along the entire column (obviously it is transferred throughout the column, but the pulling source is at the meniscus surface). I believe this is the prime reason for the maximum height of...
  3. M

    Can Branching Capillary Increase Water Height?

    Well the water will fail at some point. Water has a high tensile strength due to the cohesive forces between the molecules, but for some capillary height the water should give into the tug of war between gravity and capillary forces and cavitate (or evaporate), so an infinite column of water is...
  4. M

    Can Branching Capillary Increase Water Height?

    Yes, a 2H column of water. Why not? If I have another meniscus, wouldn't the force be doubled?
  5. M

    Can Branching Capillary Increase Water Height?

    Well then I don't understand your answer. I'll try to rephrase my question. I have a capillary that can draw water to height H. I bifurcated it near the meniscus to form two menisci. Can my new bifurcated capillary draw up 2H of water? Considering the radii of the two menisci are the same as...
  6. M

    Can Branching Capillary Increase Water Height?

    Not multiple capillaries. ONE capillary that bifurcates at the top. Can it draw up more water than a non bifurcating capillary of the same height?
  7. M

    Can Branching Capillary Increase Water Height?

    Say I have a single capillary that can raise water to height H. If I split the capillary to make another meniscus, say δ distance from the top, and both branches are of the same radius as before, will I be able to bring water up higher (i.e. could I add another H-δ high column of water to the...
  8. M

    Water Potential Theory Derivation: Xylem & Biomechanics Project Help

    I need a full derivation of Water Potential theory, specifically in tree Xylem, but any general derivation and explanation would be acceptable. I've looked everywhere, the entire library in my university, and hours in google, but I can only find qualitative descriptions. I need the full...
  9. M

    Does capillary length limit water rise in very thin capillaries?

    negligible in terms of pressure gradient, chris. One can assume that gravity is balanced entirely by adhesive forces, whereas transpiration contributes to the actual flow.
  10. M

    Does capillary length limit water rise in very thin capillaries?

    Well I've found the answer myself. Apparently the opposing adhesive forces act only on the meniscus! I thought it was a shear force that acts all along the surface of the tube. But here's another question: If I take a tube and split it to two tubes somewhere in the middle, creating...
  11. M

    Does capillary length limit water rise in 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...
  12. M

    Composition of the sun and spectrum of light

    I understand that the sun is made of 91% hydrogen, 8.7% Helium, and 0.3% other stuff. I looked up the atomic spectrum for helium and hydrogen [within the visible portion] and they leave most of the spectrum blank, albeit few lines of colour here and there, yet the white light that reaches us has...
  13. M

    What is the purpose of vibrant colors in deep-sea creatures?

    No, it's not luminescent fish, specifically, I am referring to an Anemone with a red 'top', if you will, that lives exclusively around geothermal vents. Why would anything replace the sun for a geothermal vent over the course of evolution? I doubt it made it's way down from the surface. I...
  14. M

    What is the purpose of vibrant colors in deep-sea creatures?

    I have recently been to an exhibition of deep-sea life, some of the exhibited life forms live thousands of meters under the surface where sunlight does not penetrate, it is therefore that they rely entirely on geothermal vents as a source of energy, they have never been exposed to direct...
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