Classrooms are often left with lights and fans running through empty periods and breaks. The energy waste is invisible to students and no single person feels responsible for switching things off.

Create a solution that encourages students to switch off unused lights and fans in classrooms. Study who is affected, dig past the obvious symptoms to the real root causes, and design a solution that could actually work in the real world. There is no single correct answer — what matters is the quality of your thinking, the stakeholders you consider, and how clearly you justify your chosen direction.

• Who is most affected by this problem, and how did you account for them?
• What is the single biggest risk to your solution working?
• Which assumption, if wrong, would break your whole idea?