Fb-5 Reducing Surface Tension

Aim

To demonstrate the reduction of surface tension.

Apparatus

  • Large beaker
  • Stocking
  • Water, soap solution
  • Overhead projector
  • Wire gauze mat as shown
  • Medicine dropper

Description

A stocking floats in a beaker of clean water. The addition of a few drops of soap solution reduces the surface tension sufficiently and the stocking sinks.

A large droplet of water is placed on the wire gauze mat. The surface tension of the water gives it its roughly spherical shape. The addition of a small drop of soap solution reduces its surface tension and "spreads" the drop.

Safety Notes

Reducing Surface Tension SOP-13