Question

How does the surface tension of water impact living things?

Answer 1

The tendency of the liquid or fluid surfaces to shrink into a minimum surface area and resist the external forces is called the Surface tension of that liquid.

Complete answer:
The collective intermolecular forces that exist between the like molecules of a substance are called the Cohesive forces. These forces include hydrogen bonding and van der wall forces and are seen in the water molecules. These cohesive forces between the liquid molecules are responsible for the phenomenon of surface tension. Surface tension is the property of the surface of the liquid. The tendency of the liquid molecules to resist the external forces due to the presence of cohesive forces amongst them- and achieve the state of the minimum surface area is called surface tension. The surface tension arises due to an imbalance of the intermolecular forces from all directions- in a bulk medium. The attraction between the water molecules at the liquid surface is not balanced, and a net force is present in a particular direction.

Water has a high degree of surface tension amongst its molecules- due to the presence of hydrogen bonding in them. This is the reason why the water molecules at the surface of liquids are held closely together and form an invisible film.
The major applications of surface tension in our daily lives are sticking to the small droplets of the rain, the formation of bubbles, the shape of the liquid droplets, etc.

The surface tension of water also impacts living things. Some of the examples are-
1)The ability of the water strider insects to walk on the surface of the liquid- The large legs of these insects evenly distribute their weight over the large surface area of the water. The force of their body weight is balanced by the force of the surface tension on the liquid surface. Thus, the water striders use the high surface tension of water to walk on their surface.
2)Some spiders like fisher spiders can also glide or scamper on the surface of the water by balancing their body weight with the force of surface tension.
3)The cohesion and adhesion forces present between the water molecules also help the transportation of water in the plants. The surface tension between the water molecules on the surface of the plant and the water molecules below them creates a pull on the water column. This pull is responsible for the transport of water from the roots to their leaves.
4)Some plants use the surface tension of water to disperse their seeds through the water raindrops.

Note: The phenomenon of surface tension is also observed in the human lungs. A lipoprotein surfactant reduces the surface tension in the alveoli at the air-water interface. This prevents the collapse of alveoli or lungs during the expiration part of respiration.