Chapter 12, Problem 12.73P

Interpretation Introduction

Interpretation:

The property of water that keeps plant debris on the surface of lakes and ponds is to be determined. Also, the ecological significance of this property is to be determined.

Concept introduction:

The molecules on the surface and bulk experience different intermolecular forces. The molecule in bulk is surrounded by the molecules from all sides. Therefore the net force on the molecules is zero. On the other hand, molecules on the surface have molecules only below them so the net attractive force experienced by them is in downward direction.

Due to the net attractive forces, the surface molecules will try to move into the bulk and surface area decreases.