What is the Van der Waals force and where would you see its effects?

The Van der Waals force is the weakest of all the intermolecular forces. This interaction occurs between every molecule, over very small distances, and becomes weaker the further away the two molecules are from one another. The Van der Waals force is a result of instantaneous dipoles being formed from the random motion of electrons in with the atom/molecule. Therefore if there are more electrons in the atom/molecule the stronger the attraction will be. A classic example of this is between argon atoms as these atoms a notoriously unreactive and so the only force in between them is the Van der Waals attraction, which is also aided by the large size of the atom, which in turn shows that it has many electrons.