# How the forces on a drop of water versus mercury on a glass slide influence the shape?

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I am trying to understand how fluids form particular shapes when put on a solid.
1. In the two figures,what are we taking as a system for the forces?
2. How the resultant of the forces influences the shape of the different fluids?

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BvU
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Hi,

Do not erase the template ! You have already found something, so start from there!

pranjal verma
haruspex
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I am trying to understand how fluids form particular shapes when put on a solid.
There are two parts to this:
- the forces that result in the contact angle
- the forces that control the shape of the surface elsewhere
Are you interested in analysing both of those or just one?
For the latter, consider a horizontal slice at some height. Can you relate the surface tension, the curvature and the internal pressure? (Are you familiar with the analysis of pressure in bubbles?)

pranjal verma
There are two parts to this:
- the forces that result in the contact angle
- the forces that control the shape of the surface elsewhere
Are you interested in analysing both of those or just one?
For the latter, consider a horizontal slice at some height. Can you relate the surface tension, the curvature and the internal pressure? (Are you familiar with the analysis of pressure in bubbles?)
I am Interested in determining the system on which the forces are acting and how the forces influence the contact angle of the drop.(I.e why liquid forms a specific contact angle due to resultants of all forces acting on it?)

haruspex
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Gold Member
I am Interested in determining the system on which the forces are acting and how the forces influence the contact angle of the drop.(I.e why liquid forms a specific contact angle due to resultants of all forces acting on it?)
I might have been of help with the shape elsewhere but I know little about contact angles.

pranjal verma
I might have been of help with the shape elsewhere but I know little about contact angles.
You can write what ever you know about shape of drops,I will like to learn it as well.

haruspex