Properties of Soaps

Ferrell, Alisa Whitney Young H.S.

Objectives 1. Students will learn basic properties of soap. 2. Students will be able to perform and demonstrate various cleaning different bar soaps. 3. Students will be able to perform tests using indicators such as blue litmus paper, red litmus paper, and pH paper. Materials 4 styrofoam cups (for each group) 8 pieces of pyrex (any color other than clear) 4 large jars with tops 3 bars of soap (Ivory, Zest, pure & natural were used in our demonstration) 4 sets of small bottles (for each group) labels Marking pencil or pen 1 small tube containing ground black pepper Recommended Strategy Label four cups and four vials per group A B C D. Put the three bars of soap in the large jars and add regular tap water to each. Put the top on each jar and shake them up and down . The jar left over should have tap water in it. Pour one cup of tap water and also one vial of tap water. Pass out a tray with the set of four cups to each group. Have the students observe the contents of the cups noting similarities and differences. Now go around and add a dash of pepper to each cup and have the students write down what happens to the pepper. Define terms with the help of students on the board: pH, blue litmus, red litmus, acid & base. Construct a chart noting the characteristics of the three soaps and the water. Have the students test the soaps with the indicators previously discussed i.e., blue litmus paper, red litmus paper, and pH paper. The results of these tests should also be noted on their charts. TEACHER: Make sure you have already done the experiment and constructed a
similar chart before you have them do the following : Based on the characteristics
from the chart previously made, have the students try to identify the various soaps
with the help of your chart of characteristics, which should include the results of
the tests done using the indicators and the basic characteristics of the soaps.
Based on these factors which soap would you want to use and why? See if the students
can identify the name of each brand of soap as extra credit.

The next lab period would consist of actually making a lab version of soap. This soap
could then be compared to the manufactured soaps previously observed. You may also
wish to have the students write down or note the similarities and/or differences of
these in a similar fashion to that already used.

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