Next time you’re on a plane (or a submarine!), take along some scotch tape and a balloon.
While you’re on the ground, waiting for take-off, inflate the balloon. Wrap the balloon with the tape around the equator and note how the tape constricts the balloon’s size (like a belt on your pants).
Tape the contraption to the overhead bins above and observe as your plane takes off and gains altitude.
Q. What happens?
A. Your fellow passengers give you strange looks!