Why a Chest Tube is Placed. A chest tube is placed for a variety of reasons. One reason, as you mentioned, is to help the lung re-inflate when someone has a collapsed lung, also known as a pneumothorax. In that circumstance, a chest tube is inserted along the side of the ribs to allow the lung to reinflate.
A. Osmosis is the passive movement of water from an area high in water concentration, across a semi-permeable membrane, to an area low in water concentration.
Osmosis is driven by water potential. Osmosis is a spontaneous process, so it must be the result of a downhill energy system. We call this energy system water potential. Water spontaneously moves from an area of higher water potential (energy) to an area of lower water potential (energy).