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Wastewater lesson

Class-based lesson for pupils in years 5 to 8.


Your pupils will have the opportunity to discover what wastewater is, how the liquids and solids are treated, and where it ends up. They will also find out what we used to do with wastewater many years ago.


Your pupils will be set the challenge of making a rainbow. They will carry out a liquid density experiment during which they can change the density of water to make a rainbow. They can also practice their colour-mixing skills.

Frequently asked questions:

Will I need to provide anything for this lesson?

Yes, please provide the following:

  • laptop and data projector to show a PowerPoint presentation from a memory stick
  • materials for the experiment:
  •            1 small bottle of red, blue and yellow food colouring
  •             small bag of table salt


How long does the lesson last?

It will take approximately 1.5 hours although it can be adjusted to suit the school timetable.

Do I need to teach the children anything before the lesson?


How does the lesson link to the New Zealand curriculum?

Please download the curriculum links.

Are there any posters or materials to support this lesson?

Yes, you will receive a set of posters for your class as well as background materials in electronic format.

You may also like to download the following resources:

Mangere Wastewater Treatment Plant

The Wastewater Process


Book a lesson with our experienced teacher Sally Smith. Please email her the information below at ssmith@water.co.nz or phone her on (09) 539 7316.

  1. What is your name and phone number?
  2. What is your school’s name and address?
  3. How many classes in which year group(s) would like to receive lessons?
  4. What lessons are each year group interested in? (e.g. drinking water lesson)
  5. What week(s) would you like to receive lessons? If you are interested in the water quality or bugs lessons, please let us know what week(s) you would like to receive the class-based lessons and what week(s) you would like to take the field trips.
  6. Are there any days that do not suit? (e.g. assembly day or bible class day)
  7. What is your school’s daily timetable? Please let us know the start and finish times of lessons as well as the morning tea and lunch breaks times.
  8. Would you like our teacher to visit your school to brief staff in the term prior to the lessons? If so, please let us know what days would suit and which term you would like a visit.