Plateaus rules

Plateau's rules describe the structure of soap bubbles in foam . These rules were established in the 19th century by the Belgian physicist Joseph Plateau on the basis of his experimental observations.

Plateau's rules state:

1. In one edge of the foam, three surfaces of the soap bubbles always meet at an angle of 120 ° and thus form a plateau edge.
2. At a node , four plateau edges meet at an angle of about 109 ° 28 ′ 16 ″ (the tetrahedron angle ). ${\displaystyle \arccos {\left(-{\tfrac {1}{3}}\right)}\simeq 109,4712^{\circ }}$

Arrangements of soap bubbles that do not conform to Plateau's rules are unstable. The foam tends to reshape itself to conform to the rules.

Web links

• Eric W. Weisstein : Plateau's Laws . In: MathWorld (English).