Formation of a Precipitate

An engaging activity that allows students to see the formation of a precipitate by comparing the bubbling of soap-scum in water to the bubbling of soap in water.  This site includes a student activity sheet. Students are able to see one sign of a chemical reaction, which lead to the events represented by a chemical equation.

Standards & Objectives

Essential and guiding questions: 

Ask students questions such as the following:

  • Based on your observations, do you think that soap scum is different from soap?
  • Would you consider adding soap to hard water a chemical change? Why or why not?

Lesson Variations

Blooms taxonomy level: 
Applying

Helpful Hints

Materials needed for each group:

  • Water
  • Epsom salt
  • Piece of Ivory® soap
  • Piece of paper
  • Coffee filter
  • 1 Dropper
  • 2 Popsicle sticks
  • 2 Straws
  • 6 Clear plastic cups
  • 1 Small cup
  • 1 Tablespoon
  • 1 Teaspoon

References

Contributors: