Marangoni effect Tears of wine Surface tension Commentary

James Thomson, Carlo Marangoni thermodynamics

Marangoni effect

• The Marangoni effect gives wine legs.
• The Marangoni effect stabilizes soap bubbles.
• The Marangoni effect does not cause the Cheerios effect
• but helps explains the lava lamp.
• The Marangoni effect stabilizes convection cells
• in pots of tomato soup.
• The Marangoni effect helps dry silicon wafers
• while processing integrated circuits.
• The Marangoni effect makes my leaky faucet drip
• and breaks a falling stream into a sequence of drops
• that a strobe light seems to freeze in place
• or maybe that’s just surface tension and gravity.

Tears of wine

• James Thomson observed “tears of wine”
• and explained it as the effects of differences
• of surface tensions of water and alcohol.
• Streams of droplets described as curtains or legs
• appear not because of glycerin in the wine
• but from separation of water and alcohol,
• alcohol evaporating more readily
• and having a lower surface tension,
• causing the water to flow away from it.

Surface tension

• Inside a bubble, a molecule of water
• bonds with neighbors balanced in all directions,
• but at a surface all its efforts
• pull inward and across the surface.
• Thus explains the magical ability
• of water striders to stride water,
• of beads of water to assume a spherical shape,
• and of soap bubbles to float in the air.