PURPOSE: To demonstrate surface tension.

DESCRIPTION: A thread with a loop at its center is connected across a diameter of a wire loop, as shown in the photograph at the left. Dip the wire loop into soap solution, then puncture the surface inside the thread loop. The loop expands, as shown in the photograph at the right, due to surface tension.

SUGGESTIONS:

REFERENCES: (PIRA 2A15.10) See references for Demonstration F3-04.

EQUIPMENT: Pre-assembled wire ring on handle with wooden base and meticulously hand-crafted thread with loop in center, soap solution from M4-21, pointed pencil.

SETUP TIME: 5 min.