The Barometer Story

Here is the problem a professor of physics had at the beginning of the XXth century:

“I received a call from a colleague about a student. He felt he had to give him a 0/20 to a physics question, while the student claimed a 20/20. Professor and student came to an agreement to select an impartial arbiter, and I was selected.
I read the examination question: “Show how it is possible to determine the height of a building with a barometer.”
The student replied: “I carry the barometer to the top of building, I attach a rope to it, I lower it to the ground, then I haul it back up and then I measure the length of the rope, which gives me the height of the building. ” Continue reading “The Barometer Story”