Question

If one chamber has a ${\Psi }_w$ of - 2000 kPa, and the other - 1000 kPa, which is the chamber that has the higher $\Psi$ ?

Answer 1

• Water potential (Ψ) is a measure of how freely water molecules can move in a particular system. Ψ is never positive but has a maximum value of zero, which is that of pure water at atmospheric pressure.
• Impure water or water that has solutes in it has a negative water potential value. The more solute there is, the more negative Ψ becomes since the solute molecules will attract the water molecules and restrict their freedom to move.
• Here chamber A with Ψw of - 1000 kPa has a higher Ψ than the other with Ψw of - 2000 kPa.