Activity Introduction

water-hero22-260x300Quick summary: As a ‘thought starter’ students watch a short clip about an innovative concept called Sealeaf, which explores open-sea farming. Students will investigate the global mean sea levels from 1880 to 2013. Using authentic data they will analyse a graph by considering the historic trends, calculating gradients of line segments and commenting on what the gradient represents in context. They will also have the opportunity to investigate sea level rise and who will be most affected.

Learning goals:

  • Students understand how gradient and rate of change relates to authentic data.
  • Students know how to calculate midpoints and gradient.
  • Students discover the impact of sea level rise on a global scale and how the levels are changing over time.
  • Students take personal action by undertaking further investigation and increasing community awareness.

General capabilities: Numeracy, Critical and creative thinking.

Cross-curriculum prioritySustainability OI.1

Australian Curriculum content description:

Year 9 Mathematics:

  • Solve problems involving direct proportion. Explore the relationship between graphs and equations corresponding to simple rate problems (ACMNA208)
  • Find the midpoint and gradient of a line segment (interval) on the Cartesian plane using a range of strategies, including graphing software (ACMNA294)

In line with the Australian Curriculum questions are graded to cover understanding, fluency, problem solving and reasoning.

Syllabus outcomes: MA3‑2WM

Topic: Number and Algebra, Climate change

Time required: 40-60 min

Level of teacher scaffolding: Low – teacher may need to demonstrate skills.

Resources Required: Student Worksheet, internet access, Climate Change Digital Toolbox.

Homework and extension opportunities: Students have the opportunity increase their personal awareness by writing a media release to include information from the lesson and personal research on increasing sea levels.

Key words: Cartesian plane, mid-point, gradient, coordinate points, data, sea level, climate change.

Cool Australia’s curriculum team continually reviews and refines our resources to be in line with changes to the Australian Curriculum.


Teacher Worksheet

sea-grass-biodiversity-heroTeacher Preparation:

Overarching learning goals: In this activity students will understand how to read data from a graph. Students will calculate mid-point and gradient and comment on these in context. Through the collection and consideration of the data they will discover the impact sea level rising on a global scale.

Teacher content information: This lesson is largely
based on data sourced from the CSIRO using the graph on the right.

The CSIRO and ACECRC have launched a sea level specific website 'Sea-level Rise'. The following background information can be found on the homepage of the website.  For more information on projections, data, and impacts please visit the site.

Humans have always loved the coast. Coastal regions, particularly some low-lying river deltas, have very high population densities. In excess of 150 million people live within 1 metre of high tide level, and 250 million within 5 metres of high tide. There are billions of dollars invested in coastal infrastructur

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Student Worksheet

Thought starter: Albert Einstein said, "We cannot solve our problems with the same thinking we used when we created them."

Take a look at the 'Sealeaf project'. (

Share with a partner what you like and what puzzles you about the sealeaf project.

So why would we even need Sealeaf?


The Oceans are changing. Many observations show that the ocean has been changing over the last several decades. One aspect of this is a warming ocean resulting in increase of ocean volume through thermal expansion. There has also been addition of water from glacier and ice sheets and changes in storage of water on or in the land (e.g. retention of water in man-made dams and extraction of water from aquifers). These together result in changes in sea level. This graphs shows in global mean sea level from 1880-2012. 


For more information you may like to read the CSIROs Sea Level Rise home page . Use this graph to help answer the following questions. 

Question 1

a. W
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