Surface tension gases. The pressure inside an ideal (one surface) soap bubble can be derived from thermodynamic free energy considerations. At constant temperature and particle number, , the differential Helmholtz energy is given by where is the difference in pressure inside and outside of the bubble, and is the surface tension. In equilibrium, , and so, For a spherical bubble, the volume and surface area are given simply by and Substituting these relations into the previous expression, we find which is equivalent to the Young–Laplace equation when . For real soap bubbles, the pressure is doubled due to the presence of two
Solid surface Solid surface Solid surface is a man-made material usually composed of a combination of alumina trihydrate (ATH), acrylic, epoxy or polyester resins and pigments. It is most frequently used for seamless countertop installations. Solid surface was first introduced by DuPont in 1967 under the name of Corian. Since the expiration of their patent, other manufacturers have also introduced their brands as well. Solid surface is a non-porous low-maintenance material used for surfaces such as countertops. It can mimic the appearance of granite, marble, stone, and other naturally occurring materials, and can be joined nearly invisibly by a trained craftsman. Typically