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Lesson 6-4:  Making Chlorine

Page history last edited by mariaelizabethbunn@... 5 years, 6 months ago



Engaging the Student (Entry Task) 

Developing the Ideas--Lesson

Checking for Understanding (exit ticket)

Student Handout 
Teacher/Lesson Notes

1 class period 

  • Page 3 of the full lesson plan 

View the full lesson plan here:


  1. Review the lesson, Electrolytic Cells, to determine which portions of this lesson are most appropriate for your students. 
  2. Demonstrate or allow your students to conduct the Pencil Electrolysis Lab.   You may forgo the pencils and place the wires directly in the water but you will run through many more batteries. Assess student understanding of the process of electrolysis. 
  3. Run the SE200 using these instructions and have students make observations of what they see happening.   
  4. When the run is finished, have students waft over the SE200 and describe what they smell. 
  5. Explain to the students that we can use electrolysis to generate chlorine, which is a chemical that we use to purify our drinking water. 
  6. Share the power point, Background Water Quality Chemistry with your class.  Probe for understanding of the process of making chlorine.  



For Pencil Electrolysis:

  • 9-volt battery
  • 2 wooden pencils
  • electrical tape
  • 2 4- to 6-inch pieces of small gauge insulated wire (two different colors are preferable)
  • masking tape
  • marker
  • shallow cup or bowl
  • table salt or Epsom salt
  • water
  • 1 of the following combinations (to make an acid-base indicator):
  • red cabbage and either a blender or a stove and pan
  • Ex-Lax® tablet and spoon


For running the SE200:

  • SE200 Chlorinator
  • Small Motorcycle Battery
  • Salt
  • Water 




You will use the chlorine generated in this lesson for "Lesson 6-5: Evidence for Chlorine Treatment".


  • After completing Lesson 6-5, return to SE200 and have your students brainstorm uses for this chlorine generator.
  • Use Page 3 of the full lesson plan document and have students complete the tables to document their brainstorm sessions. 







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