What happens when two magdeburg spheres are pulled after air pressure has been pumped into it?

Answer 1

it just comes apart. If air pressure is pumped out,then it would be impossible to pull apart unless air gets back in. this is the story about the Magdeburg experiment:
The Magdeburg hemispheres were a pair of large copper hemispheres with mating rims. When the rims were sealed with grease and the air was pumped out, the sphere contained a vacuum and could not be pulled apart by teams of horses. German scientist and mayor of Magdeburg, Otto von Guericke in 1650, designed the Magdeburg hemispheres. He designed them to demonstrate the air pump he had invented and the concept of atmospheric pressure. The first artificial vacuum had been produced a few years earlier by Evangelista Torricelli, and had inspired von Guericke to design the world's first vacuum pump, which consisted of a piston and cylinder with one-way flap valves. The hemispheres became popular in physics lectures as an illustration of the power of air pressure, and are still used in education. The original hemispheres are preserved in the Deutsches Museum in Munich.