Van der Waals force
From Wikipedia, the free encyclopedia
Van der Waals forces are forces that act between electrons or molecules. They are named after the Dutch scientist Johannes Diderik van der Waals (1837-1923). These forces are relatively weak, and do not include forces due to covalent bonds or electrostatic interactions. Van der Waals forces can be classified:
- Forces that act between two dipoles, named Keesom after Willem Hendrik Keesom
- Forces that act between a dipole, and a charged molecule, named Debye after Peter Debye
- Forces that act between two polarised particles, called London forces after Fritz London
[change] Example
Geckos can climb vertical surfaces: The underside of their feet is covered with very small hairs. Each hair can only transmit a very small force, but because there is a large number of these hairs the total force is sufficient for the animal to walk on ceilings and climb vertical surfaces. The forces involved are about 250 N.[1]
