The sulfur must be in the form of a very fine powder. Sulfur floats on water. The surface tension of the water is high, and the water is unable to wet the sulfur. The density of the sulfur is greater than that of the water. A small amount of detergent, just enough to go unnoticed on fingertips, will sufficiently lower the surface tension of the water to allow it to wet the sulfur, which immediately sinks.

Using the balance to lift the ring from the waterÕs surface is the most difficult part of this experiment.

Reference

(See Experiment C33 of Doing Chemistry.)