[staticautomatic]

I had a science test in high school with a question that involved something to do with calculating the air pressure inside an airplane at some high altitude. I went up to to the teacher and said "is this a trick question? Airplanes are pressurized at that altitude" He looked around the room nervously and then told me to assume the airplane wasn't pressurized.

[Stratoscope]

Ah yes, the notorious spherical cow!

https://en.wikipedia.org/wiki/Spherical_cow