Surface Tension Force Explained
Surface tension is the tendency of liquid surfaces to shrink into the minimum surface area possible.
This phenomenon arises due to the cohesive forces between liquid molecules.
Understanding Cohesion vs. Adhesion
- Cohesion: The attraction between molecules of the same substance. Within a liquid, molecules are pulled equally in all directions by neighboring molecules. However, at the surface, molecules lack neighbors above them, leading to a net inward pull.
- Adhesion: The attraction between molecules of different substances.
The net inward pull experienced by surface molecules, caused by the stronger attraction to molecules within the liquid (cohesion), creates tension along the surface. This cohesive force is the primary reason for surface tension.
Therefore, surface tension is caused by the force of cohesion at the free surface.
Important Questions from Surface Tension
Which of the following statements is NOT correct about surface tension?
If a liquid droplet and a soap bubble are formed from the same liquid and have the same radius $R$, how does the excess pressure inside the soap bubble ($\Delta P_{bubble}$) compare to the excess pressure inside the liquid droplet ($\Delta P_{droplet}$)?
Mercury does NOT wet the glass. This is due to the property of the liquid known as
________ is a surface phenomenon.
A liquid drop is spherical in shape due to
