In a Lather: Do Suds Matter?

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Author: Sofia PC

Grade Level: 6th-8th; Type: Consumer Science and Chemistry


To discover if a sud-free cleaning agent works just as well as one that generates suds.

Research Questions:

  • What happens when bubbles start forming and foam up?
  • Does sudsy action get things cleaner?

Many cleaners are marketed for their “rich lather,” which suggests that more bubbles and foam lead to more cleanliness. But is it true? What exactly do these bubbles do?


  • Two soiled towels with obvious stains
  • Sudsy cleaning agent (can be shampoo, dishwashing liquid, or detergent)
  • Non-sudsy cleaning agent
  • Two buckets to hold the soiled towels
  • Water

Experimental Procedure:

  1. Take the two equally soiled towels and place each in a separate bucket. Label one bucket "sudsy" and one "non-sudsy."
  2. Add the cleaning agents accordingly.
  3. Add equal amounts of water to both buckets.
  4. Wash for the same amount of time at the same pressure for both towels.
  5. Now observe which one is cleaner.
  6. Record your results.

Terms/Concepts: Bubbles; Suds

References: Wikipedia's Soap Bubble Page; BubblesThe Science of Soap Films and Soap Bubbles by Cyril Isenberg (Dover, 1992). Soap-Bubbles and the Forces that Mould Them, by C. V. Boys (Dover reprint, 1890) is a classic Victorian exposition, based on a series of lectures originally delivered "before a juvenile audience."

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