The effect of soap on surface tension

Select a large plate and rinse it unless you are sure that it is very clean. Fill the plate with cold water and let it stand for a time on a table unless the water is at rest. Sprinkle some talcum powder lightly over the surface of the water. Wet a piece of soap in water and touch it to the water near the edge of the plate. The talcum grind will be drawn to the opposite side of the plate at once.