  The physical mechanism of elasticity of liquid surfaces coated with colloidal
particles is proposed. It is suggested that particles are separated by water
clearings and the capillary interaction between them is negligible. The case is
treated when the colloidal layer is deformed normally to its surface. The
elasticity arises as an interfacial effect. The effective Young modulus of a
surface depends on the interfacial tension, equilibrium contact angle, radius
of colloidal particles and their surface density. For the nanometrically scaled
particles the line tension becomes essential and has an influence on the
effective Young modulus.
