Ever since the idea of just-in-time inventories was invented, I thought it was a bonkers idea. It makes sense only if you assume that there is never going to be a major disruptive event that will disrupt supply. I think that the pandemic and now the war in the Ukraine have highlighted the folly of such assumptions.

The potentially devastating consequences of a drive for efficiency to the nth degree are shown in this science fiction story. In The Cold Equations, Tom Godwin posits the idea of a supply spaceship that has almost precisely the right amount of fuel for its return journey, taking into account weight and distance. What happens when the pilot discovers a stowaway on board? I won't spoil the story for you by telling you (read it, especially if part of your job is to discuss moral issues with your students), but what a great starting point for a spreadsheet exercise! Can you construct a simple model showing what happens to fuel consumption when one of the critical factors (weight or distance) goes over a certain limit?

This activity can be enriched by asking the pupils to do research into this area -- not necessarily in the area of space flight, but in the more accessible realm of fuel consumption by cars.