1, Fig. I shows a gas bubble confined in a 0.0002-in.-diameter capillary tube. The tube is wet by water in the presence of gas and by oil in the presence of gas. The bubble is motionless. The contact angles, measured through the wetting phases, are 10 and 30 for the water and oil, respectively. The IFT between the water and gas, g, is 70dynes/cm and that between the oil and gas, 80, is 33 dynes/cm. Calculate the pressure difference between the oil and water phases. 2 , A researcher assembles a capillary tube (Fig. 2) to simulate a porous medium. It is known that water wets the capillary tube glass with a contact angle of 300 . The tube is placed in a horizontal position and completely filled with water. The water is at atmosphere pressure. The tube is then flooded with oil; i.e., oil is injected, displacing the water. The IFT between the oil and water is 30 dynes /cm. what pressure would be required in the oil phase to displace the water? That is, at what pressure would be the displacement start, and what pressure would be required to displace the water completely? (Assume that the water is in contact with a water reservoir at the outlet end and that capillary forces do not exist at that point.)