Mathematical modelling: Screentime footprint

In this sequence, students explore how everyday digital behaviours contribute to CO₂ emissions and how mathematics can help us understand and respond to this issue. They begin by examining international comparisons, then look at how Australia’s digital use is changing, investigate the growth of app file sizes, and finally calculate their own digital CO₂ footprints. Across the lessons, students are encouraged not just to analyse data, but to think critically about the choices individuals and communities can make to reduce emissions. The sequence highlights mathematics as a decision-making tool, connecting classroom learning with questions of environmental responsibility.

The process of mathematical modelling in this sequence

Framing a PROBLEM IN CONTEXT

The lessons position climate change and digital technology use as pressing, real-world problems. Students are asked to consider how countries, communities, and individuals contribute to CO₂ emissions, and to think about what the future might look like if current trends continue.

Formulating a MATHEMATICAL PROBLEM

Students engage with these situations by defining quantities such as total CO₂ emissions, population, download rates and app sizes, and represent the relationships between them. This often requires simplifying messy, real-world data into manageable forms, including using a single rate for streaming or modelling growth with a straight line. These choices allow students to see how assumptions shape the kinds of answers mathematics can give.

Solving to produce a MATHEMATICAL RESULT

Students use their models to generate results that shed light on the problems at hand. They calculate CO₂ emissions per person, construct linear graphs to predict digital growth, and estimate the composition and total amount of CO₂ emissions from their own technology use. These results provide evidence that can be weighed and compared, offering insight into both the scale of the problem and the role of individual behaviour within it.

Interpreting the RESULTS IN CONTEXT

The results prompt reflection on what they mean for the world students inhabit. Patterns in the data raise questions about fairness between countries, about whether Australia’s digital consumption is sustainable, and about the surprising impact of everyday activities such as emailing or video calls. Students are invited to connect these findings to their own choices and to discuss what kinds of actions, at personal or collective levels, could make a meaningful difference to reducing CO₂ emissions.

Evaluating if it is an appropriate solution for the PROBLEM IN CONTEXT

Students evaluate how well their models serve the purpose of decision-making. They consider the reliability of secondary data, the limitations of linear growth assumptions, and the simplifications made in CO₂ emission estimates. By questioning these aspects, they come to see mathematics not as providing final answers, but as a way of informing judgement about complex problems.