Cup of Joe - Capillarity in Concrete and Wood

[@koenraadprincen7212]

Capillary rise stops at about 33 ft (10 m), you need to check *Jurin's Law.*
There is a force upwards due to the contact angle between water and the material (wood, brick, concrete, mortar,...) and there is a force downwards due to gravity acting on the water column which leeds to a higher water pressure at the fee water surface (your bucket).
A higer water pressure at the free water surface level means a water pressure below 1 atm at the top of your capillary water column (equilibrium). And because you can not go below absolute vacuum, the height of your water column is limited to 33ft or 10m.
_Trees can grow above 33 ft because of _*_internal_*_ evaporation (day) and condensation (night)._

[@PurePremium2]

You might want to look into negative presssures in biological systems.

[@koenraadprincen7212]

@@PurePremium2 Yes and those who "believe" in negative pressures will tell you that you can pull on a liquid as if it's a solid.
If negative pressures where possible in a liquid, we wouldn't have cavity in centrifugal pumps.
Once you reach a very low pressure, water will start to boil at room temperature...

[@JoeLstiburek]

LaPlace-Young and Kelvin make it clear that Jurin is incorrect.

[@koenraadprincen7212]

@@JoeLstiburek 1. The Kelvin-law is thermodynamical law and thermodynamical laws can not be used on their own to describe a physical phenomenon (like capillary rise).
2. The Kelvin-law describes how the vapor pressure will change *AFTER* the liquid surface has become spherical.
3. The Kelvin-law *does not discribe how that spherical surface has been or will be formed.*
Such a surface is the result of the surface tension of a liquid and the hydrophilic property of a material.
4. The Jurin-law is a physical law and gives the relation between the surface tension, the liquid density the rising height and the radius of the capillary tube.
And yes, the radius is also in the denominator which would indicate that the rising height goes to infinity when the radius goes to zero.
5. But other physical laws like hydrostatic pressure in a liquid column and that no pressure can be lower then the absolute vaccum are still valid even though they don't appear in the formula of the capillary rise.
*These two laws cap off the maximum rise to about 10m or 33 feet.*
It's like the buckling formula of Euler which gives the maximum normal load a column can take, that load is also limited by the maximum allowable compressive tension of the material even though that tension doesn't show up in the formula.