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Lesson 6-5:  Evidence for Chlorine Treatment

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 


View the full lesson plan here:


Supplemental Article on how Chlorine added to water kills bacteria:



In this lab, students will ask the question "What effect does the concentration of chlorine have on organic molecules?". Students use food coloring (an organic molecule) to model bacteria (an organic organism). 


  • SE2000 Electrochlorinator as a source of chlorine
  • Student Instructions and Data Sheet (1 per group) 
  • Stock solution of blue food color
  • 100 ml beaker
  • Colorimeter
  • Laptop
  • Cuvette
  • Pipette
  • Timer 

Have students write a conclusion for their experiment that answers the investigative question.


  • What were the Big Ideas (important concepts) from this investigation? 
    • Include supporting data from your data table to support each of your big ideas.
    • Explain how these data support your claim.
  • Provide a scientific explanation for the data you collected.






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