So what caused this steel railroad tanker car to be crushed like a flimsy, aluminium pop can? The answer is air pressure. There was enough of a difference in air pressure between the air pressure inside the tanker and the air pressure of the air surrounding the tanker that the steel in the tanker gave out.
image/text credit: Tom Brattain
But what is air pressure? How was the difference in air pressure established? Why does the difference in air pressure cause the tanker to implode?A railroad tank car demonstration imploding after placing a vacuum on the tank with the vacuum safety valves disabled or removed.
This hose is actually a part of a vacuum pump which was gradually pulling air out of the huge tanker. It isn’t evident from the video how long this vacuum pump was working.We now understand of how immense the pressure of the atmosphere is at sea level.
This air pressure has always had enough force to crush this tanker however, since the tanker has had the same amount of air pressure inside as it does on the outside, the tanker was not crushed.