Published on Mar 28, 2020
The objective: To what extent does the surface tension of water decrease as the amount of detergent is increased? If adding detergent to distilled water affects its surface tension, then capillary rise will decrease with increasing concentration of detergent. It should reach a point where the addition of detergent no longer affects the height of the solution in the capillary tube.
I started with distilled water and continually added small amounts of detegent to the water. I took capillary height readings after each addition of soap. I continued until the capillary height remainded constant even when adding more soap.
The capillary height started at 16mm for distilled water, then gradually got lower until it stayed at 6mm.
The results supported my hypothesis and verified information that I read in a reference book which stated that the surface tension of a soap solution is approximately one third that of distilled water. In my experiment, the final capillary height of the soap solution was 37.5 percent of the capillary height of the distilled water.
This experiment is to measurd the affect of soap on the surface tension of distilled water
Science Fair Project done By Elizabeth M. Hatakeyama