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

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Discussion Overview

The discussion revolves around the behavior of mercury in a glass capillary tube, particularly why mercury rises despite its strong cohesive forces. Participants explore the concepts of cohesion, adhesion, and hydrostatic pressure in the context of capillary action.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions why mercury rises in a capillary tube if it has strong cohesive forces that prevent it from adhering to the glass.
  • Another participant asserts that mercury will not rise above the surface of the bulk liquid and will actually be below the surface in the capillary tube.
  • A subsequent post reiterates the previous point about mercury's level in the capillary being below the bulk liquid's surface and seeks clarification on why mercury does not completely exit the tube.
  • A later reply introduces the idea that the balance of cohesive forces and adhesive forces results in a downward component that counteracts the hydrostatic pressure, leading to a lower level of mercury in the tube.

Areas of Agreement / Disagreement

Participants do not reach a consensus; there are competing views regarding the behavior of mercury in the capillary tube and the interplay of cohesive and adhesive forces.

Contextual Notes

The discussion highlights the complexity of capillary action and the specific conditions under which mercury behaves differently from other liquids, such as water. Assumptions about the nature of cohesive and adhesive forces are not fully explored.

Abbas0000
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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 shorter and shorter.The reason said to be due to strong cohesion mercury has which makes it reluctant to stick to capillary walls and go higher unlike water.
My Question:
If mercury has such strong cohesion why it's seen to rise,although small, in our glass tube?

I'll appreciate any help !
 
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Ygggdrasil said:
Mercury in a glass capillary tube will not rise above the surface of the bulk liquid; the level of mercury in the capillary will actually be below the surface of he liquid:
https://en.eewikipedia.org/wiki/Capillary_action
Well it's right but why it's not totally getting out of tube?
 
Abbas0000 said:
Well it's right but why it's not totally getting out of tube?
The resultant of its cohesive forces and the forces adhering to the glass has a downwards component which acts against the force due to the hydrostatic pressure of the liquid. Net result is a lower level. The mercury is pulled downwards.
 

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