An impressive hands-on demonstration of adhesive surface tension. Hang the 7.5-cm glass disk by its three precisely coordinated hanging cords over a container of liquid. Then let the disk rest on the surface of the liquid. Students can feel the force required to pull the disk free. For quantitative results, a spring scale can be used to measure the actual force and compare it to the weight of the disk alone. Different liquids can also be compared to determine their adhesive surface tension.