Surface tension, γ, can be thought of as energy per unit area, a. so, the change in energy, δe, of a surface can be related to surface tension and the change in surface area, δa. δe=γδa what amount of energy is required to change a spherical drop of water with a diameter of 1.40 mm to three smaller spherical drops of equal size? the surface tension, γ, of water at room temperature is 72.0 mj/m2. you\'ll need the surface area of a sphere 4π r2 and the volume of a sphere 4/3 ·π r3.