(a) With reference to the Young's equation define the difference between a surface tension, and interfacial tension and a surface energy. (b) Explaining any assumptions made, describe how you would use a Zisman plot to find the surface energy of a flat substrate. (c) Why is the Zisman approach consider a 1 parameter method? (d) Describe how you would use a Fowkes approach to find the surface energy of a flat substrate. (e) Why is the Fowkes approach a 2 parameter method