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Name: Marc
Status: educator
Age: 20s
Location: N/A
Country: N/A
Date: 1999-2001
Question:
Hello, I was talking with my students when one's asked me a question: Why soap make bubbles, and does a soap is more efficient when there's more bubble (lather).?

Replies:
Soap makes bubbles by lowering the surface tension of water. Surface tension is the force acting on the surface of water in the direction of the surface -- like a skin. By reducing this force it becomes possible to stretch the surface skin without is breaking -- and so bubbles.

While it is roughly true that the more lather the lower the surface tension, that is not completely true there are some "soaps" which reduce the surface tension of water quite effectively without producing a great deal of foam or lather. These soaps are used in laundry and glass washing machines where one wants the cleaning action of the soap without very much foam.

Vince Calder


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