Ronald Rovers asks why are governments building wind turbines so that people can use electricity to dry their washing.  Why not use the wind directly and cut out all the technology, he asks.  It’s a good question which many people in the UK at least have answered for themselves.  We have on average more space for washing lines than the Dutch do, of course.  Rovers has done the space-time maths to show what’s spent and saved.  This begins:

“So lets do some math: the space-time of laundry drying.

With space-time calculations, its only about system value: calculated from solar energy input, the real driver of the earth ( closed) system, the only source that does not deplete our system. And to capture and intercept solar energy requires land, to convert it in a useful form: which gives a certain flux over time to be captured from a standard land unit. To convert it into food, energy or mass resources.  For laundry drying we take the example of 1 drying cycle, out of 200 a year, with around 4 hours of drying outside for one cycle.  …”

Of course, it’s not just washer/drying machines, this kind of calculus applies to many things we do.  There’s much in here for a capable environmental science class to get to grips with in an holistic way.