Blue - Do the Maths on Plastic Toothbrushes

Blue - Do the Maths on Plastic Toothbrushes

Lesson 1 of 4 in this unit

  • Secondary
  • Year 7 - 8
  • Mathematics
  • Environmental
  • Biodiversity
  • Conservation
  • Oceans
  • Water
  • ...

Lesson summary

This lesson incorporates clips from Blue The Film as learning inspiration. Students delve deep into the mathematics behind one of the big environmental problems of today: plastic waste. Students explore what it would mean if we addressed one part of this problem; specifically cutting down on the millions of plastic toothbrushes that are thrown away in Australia each year. This lesson invites students to critically evaluate statistics and use relevant data to calculate the impact of this environmental change.

Learning intentions:

Students will...

  • understand the positive impacts of reducing plastic waste through mathematical investigation. 

Success criteria:

Students can...

  • identify and use statistics
  • identify the impact we have on our planet
  • calculate the impact of cutting back on the amount of toothbrushes we waste each year.

Lesson guides and printables

Lesson Plan
Student Worksheet
Teacher Content Info

Lesson details

Curriculum mapping

Australian Curriculum content descriptions:

Year 7 Mathematics: Identify and investigate issues involving numerical data collected from primary and secondary sources (ACMSP169)

Syllabus outcomes:  MA4-1WM, MA4-3WM, MA4-19SP

General capabilities: Critical and Creative Thinking, Ethical Understanding

Cross-curriculum priority: Sustainability OI.1, OI.6

Relevant parts of Year 7 Mathematics achievement standards: Students identify issues involving the collection of continuous data. They describe the relationship between the median and mean in data displays.

Unit of work: Blue The Film – Mathematics – Year 7 – 10

Time required: 60 mins +

Level of teacher scaffolding: Medium – Lead students in discussion.

Resources required

  • Student Worksheet – one copy per student
  • Device capable of presenting a clip to the class
  • Plastic Statistics Factsheet (one copy per student)
  • Sticky-notes


This lesson is designed to build students’ competencies in the following skills:

  • Communication
  • Collaboration
  • Creativity
  • Critical thinking
  • Empathy

Additional info

Blue is a feature documentary film charting the drastic decline in the health of our oceans. With more than half of all marine life lost and the expansion of the industrialization of the seas, the film sets out the challenges we are facing and the opportunities for positive change. Blue changes the way we think about our liquid world and inspires the audience to action. Find out how to screen or download the film here. Along with the film is an ambitious global campaign to create advocacy and behaviour change through the #oceanguardian movement. To become an ocean guardian, see the website.

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