Fluids have attractive electric forces among molecules {cohesion}|. Surface tension has cohesion.
Inside fluid, cohesive forces are symmetric and cancel each other. At fluid surfaces, cohesion pulls molecules closer together {surface tension}|, to make surface density more than inside density. Increased-surface-density layer width is 20 molecules. Air above fluid has small density and has little attraction for fluid. Surface chemical potential is greater than inside fluid, because net force is more, and fluid is denser and so more organized.
floating
Surface tension can make density great enough to float objects, such as steel pins.
examples
Glue, waterproofing, detergents, wicks in candles, blotters, towels, bubbles, milk drops, camphor dance, soap film, salts, and needles on water illustrate surface tension.
drops
Droplets have more surface area and high surface tension.
factors
Solute can lower solvent-molecule cohesion by disrupting cohesive forces and lowering chemical potential. Soaps and detergents lessen water surface tension by blocking water-molecule attractions. However, ions in water increase surface tension by increasing electric forces.
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Date Modified: 2022.0225