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The Water Princess (Math/Science – Percentage Change)

SUBJECTS Math, Science
GRADE LEVEL Senior (9-12)
PLEDGE 2 - Human Right to Water

Resources Needed:

  1. The Water Princess by Susan Verde or Video: The Water Princess Read by Georgie Badiel
  2. Computers with spreadsheet software or access to Google Sheets
  3. Template spreadsheet for students
  4. Optional: slide deck


  1. Read The Water Princess aloud to the class (or show the video reading).
  2. Ask students what percentage of the world they think has access to safely managed drinking water.
  3. Share the fact that “[w]hile the number of people lacking safely managed services has decreased significantly in recent years, 2 billion people still lacked access to safely managed drinking water services in 2020 (UN-Water, 2021)”. Ask students what percentage of the world population that is (~25%). Then ask whether they think this is better or worse than before.


  1. Tell students you will be calculating percentage change using data on global access to water from 2000 and 2020. If necessary, review what percentage change means.
  2. Have students open the spreadsheet, make a copy, and follow the instructions.

Follow Up Activities:

  1. Discuss the advantage of using percentage change to assess change (instead of the raw numbers).
  2. What does the data show us? Is the situation getting better or worse? 
  3. If current trends persist, only 81% and 67% of the world’s population will have access to safely managed water and sanitation services, respectively, by 2030 (WHO and UNICEF, 2021). Is that good enough?
  4. Have students graph the data.
  5. Have students interpret the data.