To calculate the surface tension of water using the capillary rise method, we can use the Jurin's Law formula:h = 2 * * cos / * g * r where:h = capillary rise height of the liquid column = 3 cm = 0.03 m = surface tension what we want to find = contact angle between the liquid and the capillary tube for water, it is approximately 0, so cos = 1 = density of the liquid for water at 25C, it is approximately 997 kg/m g = acceleration due to gravity approximately 9.81 m/s r = radius of the capillary tube diameter is 0.8 mm, so radius is 0.4 mm = 0.0004 m Rearranging the formula to solve for : = * g * r * h / 2 * cos Plugging in the values: = 997 kg/m * 9.81 m/s * 0.0004 m * 0.03 m / 2 * 1 = 0.117 kg * m/s / 2 = 0.0585 kg * m/sSo, the surface tension of water at 25C is approximately 0.0585 N/m Newtons per meter .