1. Properties of the Liquid State: Surface Tension
Air
Liquid Surface
Surface Molecule
Bulk Liquid
Net force directed down and into the bulk solution
No net force. Complete cancelation.
Surface Tension: The energy required to increase the surface area by a specified amount.

2. Properties of the Liquid State: Surface Tension
Molecules at surface are pulled inward....
Minimum Surface Area: Sphere
Shape changes to reduce the number of surface molecules....
...or reduce the surface area to it’s minimum value.
Water “blob” in zero gravity on board the International Space Station

3. Surface Tension: Examples
Water Strider