Crushing of Steel Drum
Dan Stamm, a physics teacher at Campbell High School in Smyrna, GA constructed a platform for heating water in a steel drum. The drums used had a surface area of about 3000 square inches. The force of one atmosphere of pressure on that area is about 44,000 lbs or 22 tons! Nevertheless, such cans can be made of reasonably thin steel because the same force normally acts outward from the inside of the vessel.
Atmospheric pressure demos
Producing a vacuum by boiling water