Year level: 6

Strand: Statistics

Lesson length: 50–60 mins

In this lesson, students engage with megalitres in a real-world context by exploring dam water storage capacities across Australia.

They interpret and compare real-world data sets and analyse graphs in terms of their range and shape.

This lesson is the third of 5 lessons that connect the cross-curriculum priority of Sustainability with Number, Measurement and Statistics. It can also complement the science content description AC9S6U04 .

Achievement standard

Students compare distributions of discrete and continuous numerical and ordinal categorical data sets as part of their statistical investigations, using digital tools.

Content descriptions

Students interpret and compare data sets for ordinal and nominal categorical, discrete and continuous numerical variables using comparative displays or visualisations and digital tools; compare distributions in terms of mode, range and shape. AC9M6ST01

General capabilities

Numeracy

Sustainability

Refer to the Exit ticket on slide 8.

List one thing that you:

  • found interesting or surprising in today’s lesson
  • are wondering about from today’s lesson.

Some students may:

  • have difficulty working with numbers beyond 1 million
  • find it challenging to identify and interpret real-world data.

Prerequisite student knowledge

  • Familiarity with units of measure for capacity
  • Interpret numbers beyond a million
  • Familiarity with line graphs

Language

  • litres, kilolitre, megalitre
  • water storage levels
  • capacity
  • line graph
  • range
  • shape of graph

What you need:

Learning goals

Learning intention

  • We are learning to interpret and work with megalitres in a real-world context.
  • We are learning to interpret and compare real-world data sets and analyse graphs in terms of their range and shape.

Success criteria

By the end of this lesson, students can:

  • interpret megalitres in a real-world context
  • determine the range for a data set
  • interpret and compare real-world data sets
  • describe the changes in shape of a graph over time.

Why are we learning about this?

Learning about megalitres and water storage shows us not only how much water is available but also the need to use it wisely since there's only a limited supply.

By examining water levels in different cities, we discover that water isn't equally available everywhere, which can be due to varying rainfall or how we use our water locally.

Information is increasingly being shared through data and visual displays, making the ability to understand and interpreting them an increasingly important skill to master.

Learning hook 5–10 mins

Download and use the teacher’s slides to accompany your teaching. You will find this in the ‘What you need’ section.

  • Project slide 4 of the teacher’s slides.

How many litres of water are in an Olympic-sized swimming pool?

The dimensions of an Olympic swimming pool are 50 m × 25 m × 2 m (2 metres is the minimum depth, can go up to 3 metres).

Where possible, bring an empty 1-litre container to show students the size, as this might help them with their estimation. Additionally, also consider bringing a 10 cm × 10 cm × 10 cm MAB cube and highlight that 1 litre of water takes up the same amount of space as the MAB cube, that is, 1 litre of water can fit exactly into the MAB cube.

Collect students’ estimates by asking them to write their estimates on a mini whiteboard, enter them directly into an Excel spreadsheet for easy sorting, or by sharing a link to a survey for them to respond to.

  • Project the results and have students analyse the class estimates and discuss as a whole class:
    • the lowest/highest estimate
    • the difference between the lowest and highest estimates.

Have calculators available to enable all students to find the difference readily.

  • Display slide 5 to reveal how many litres are in an Olympic swimming pool and ask students to consider the size of the number.

What units of measure could we use to make this measurement easier to read?

Note that 50 m × 25 m × 2 m = 2500 cubic metres and there are 1000 litres in 1 cubic metre.

Therefore, the total number of litres is 2500 × 1000 = 2,500,000 litres, which is the same as 2,500 kilolitres or 2.5 megalitres.

Show slide 6 to help students appreciate the physical size of 1 kilolitre and 1 megalitre.

Explore 40–45mins mins

Introduction (10 mins)

  • Pose the question ‘Where does our water come from?’ to lead the conversation to water storages and water storage levels.
  • Display information about from your state or territory water authority or search ‘BOM Australia water storage dashboard’ and give students a moment to consider the information. Spend some time exploring the information with the students as a whole class:
    • discuss the units used to measure water storage, focusing on the megalitre (ML) unit and its significance
    • discuss the maximum capacity of water storage and current of water storage percentage
    • encourage students to draw conclusions about water usage patterns and climate conditions.

Lesson activity

Organise students in groups of 2–3, to select a capital city and compare its current and past water storage levels. 

Introduce the lesson activity: comparing water storage levels (slide 7). The activity assumes that students will be able to access the BOM Australia - water storage level dashboard or similar website.

Check to see if students have any additional clarifying questions before starting the activity. 

Observe how students are approaching the activity, supporting them with language and enabling and extending prompts as required.

Differentiation (support)

Have students use a calculator so that their focus remains on interpreting the data and graphs in a real-world context, rather than on performing the subtracting large numbers accurately. 

Check to see that students can interpret the data.

  • What does percentage full tell us about the water storage level for that city? Is that more or less than last year’s water level? How do you know?
  • Where can we find out how much water is in the dam right now?
  • Refer to the dam’s capacity. What do you think this number represents?

 Differentiation (extend)

  • Which of the two locations has the highest water storage level? Does that location also have the highest percentage full? Explain your reasoning. 
  • Which city has the greatest variation in its water storage levels from previous year to current? Can you think of some reasons as to why?

Summary and reflection 5 mins

Give each group 1–2 minutes to share their 3 points of interest and why they found them interesting. Ideally, each group member should present at least 1 point of interest.