Explain what happens to a plastic bag attached to a can when the can is heated and then cooled.

When the bottom of the can is heated, the air inside the can and the plastic bag heats up. The heated air expands, causing the plastic bag to inflate or swell.

When the burner is removed and the system cools, the air inside the can and bag contracts. This causes the pressure inside to decrease significantly. The higher atmospheric pressure outside then pushes the flexible plastic bag inwards, causing it to collapse into the can.

The plastic bag will first inflate when heated, and then collapse or be sucked into the can when cooled.