| Aim | The aim of this experiment is to determine the surface tension of water by the capillary rise method. |
| Apparatus Required | A glass capillary tube Distilled water A beaker or other container to hold the water A ruler or meter stick A stopwatch or timer |
| Theory | Surface tension is a property of liquids that results from the attractive forces between the molecules at the surface of the liquid. It is defined as the force per unit length acting perpendicular to the surface of the liquid. The capillary rise method is a commonly used technique to measure the surface tension of liquids. In this method, a capillary tube is partially immersed in the liquid, and the liquid rises in the tube due to the surface tension of the liquid. The height of the rise is proportional to the surface tension of the liquid, as well as the radius of the capillary tube. The formula is given as: T = 4ghd/2r where T is the surface tension of the liquid, g is the acceleration due to gravity, h is the height of the rise of the liquid in the capillary tube, d is the density of the liquid, and r is the radius of the capillary tube. |
| Procedure | Clean the capillary tube with distilled water to ensure there is no dust or dirt on the inner surface. Fill the beaker or container with distilled water. Insert the capillary tube into the water, making sure it is vertical and that the water level is above the end of the tube. Observe the rise of the water in the capillary tube. Measure the height of the rise of the water in the capillary tube above the surface of the water in the container using a ruler or meter stick. Repeat the experiment several times, taking care to use the same capillary tube and container of water each time. Calculate the average height of the rise of the water in the capillary tube. Using the formula for the capillary rise method, calculate the surface tension of the water. |
| Observation and Result | Result: The result of the experiment is the surface tension of the water, calculated using the capillary rise method. Observation: During the experiment, we observe that the water rises in the capillary tube due to the surface tension of the liquid. The height of the rise is measured using a ruler or meter stick. By repeating the experiment several times and calculating the average height of the rise, we can obtain a more accurate measurement of the surface tension of the water. This experiment demonstrates the principle of surface tension and how it can be measured using the capillary rise method. The result obtained can be compared to the accepted value of the surface tension of water to evaluate the accuracy of the experiment. |
