Getting The Soap Out!

based on 26 ratings
Author: Muriel Gerhard, Ed.D.
High School
Difficulty of Project
Safety Issues

Wear safety glasses, apron and rubber gloves

Material Availability

The basic materials can be obtained from the local super market or grocery store. The equipment is readily available from the high school science laboratory. Any other purchases can be made from Chem Scientific, a leading supplier of inexpensive apparatus, chemicals and materials for science education.

Approximate Time Required to Complete the Project

1 to 2 weeks. This includes collection, recording and analysis of data, summary of results and completion of bibliography.


To design and conduct an experiment to determine which of the following substances, table salt, Epsom salt, sugar or baking soda would be most effective in removing soap from water?

Materials and Equipment Required

Water, powdered soap, Epsom salt, sodium chloride (table salt), sugar, baking soda, 5 plastic cups or glass jars,  a large beaker, a graduated cylinder, 5 test tubes and holder, ruler, plastic spoons, stirrers, a watch with second hand, filter paper, a funnel,   scissors, safety glasses, apron or shirt to serve as lab coat and paper towels.


Background Information

On the information level, this experiment serves to acquaint students with current information on a major waste and recycling question, how to remove soap and detergent from water. Students test various chemicals and discover how the process of precipitation is utilized to remove the soap and restore the water for future use.

On the level of experimenting, this project serves to acquaint students with the essential processes of sciencing such as the importance of the use of a control, of identifying dependent and independent variables, of data collection, of pictorial and graphic presentation of data and of being able to make better judgments as to the validity and reliability of their findings. They take on the role of scientists and in the process they learn to act as one.

Research Terms
water pollution
water purification
water softening
water quality
water treatment
hard water
soft Water
physical change
chemical change

Research Questions

  • How do water purification plants remove soap from water?
  • Do powdered soaps form solutions when added to water?
  • What are powdered soaps made of?
  • Are there chemicals that are used specifically to remove soap and soap scum from water, from different surfaces such as shower doors and bathtubs?  
  • What is filtration?
  • How is filtration used in water purification?

Terms, Concepts and Questions to Start Background Research

  • What is a control?  A control is the variable that is not changed in the experiment.
  • What purpose does a control serve? It is used to make comparisons as to what changed or possibly caused the change.
  • What are variables?  Variables are factors that can be changed in an experiment.
  • What is an independent variable? The independent variable is the one that is changed in the experiment.
  • What is a dependent variable? The dependent variable is the one that changes as a result of the change in the independent variable.
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