It would be very unadvisable to place a can of soup over a campfire without venting the can. As the can heats up, it may explode. The kinetic-molecular theory explains why. The air inside the rigid can of soup is given more kinetic energy by the heat coming from the campfire. The kinetic energy causes the air molecules to move faster and they impact the container walls more frequently and with more force. The increase in pressure inside may eventually exceed the strength of the can and it will explode. An additional factor is that the soup may begin boiling which will then aid even more gas and more pressure to the inside of the can.
Mike wanted to know what would happen if he heated up an egg in the microwave. Mike place a whole egg shell and all in the microwave and turned it on. At first nothing seemed to be happening the egg was just going around on the turntable. Then suddenly after about 45 seconds the egg exploded. The shell cracked and yolk splattered every where. Sam could see steam coming of the egg so he waited a minute for it to cool down before he cleaned it up.
Where molecules impacting the inside of the shell more ore less often before heating the egg??