After the partition has been moved to the right end of the volume, we can open the door again (Figure \PageIndex1c), equalizing the molecule’s average pressure on both sides of the partition, an...After the partition has been moved to the right end of the volume, we can open the door again (Figure \PageIndex1c), equalizing the molecule’s average pressure on both sides of the partition, and then slowly move the partition back to the middle of the volume – without its resistance, i.e.