AP BIOLOGY

Detailed explanation-1: -Water striders are able to walk on top of water due to a combination of several factors. Water striders use the high surface tension of water and long, hydrophobic legs to help them stay above water.

Detailed explanation-2: -Where the water molecules meet the air, their cohesion creates surface tension. This surface tension creates a thin skin on the water. This skin on the water is strong enough to support lightweight objects. Animals that walk on water spread their weight over a large area so they won’t break through the water’s skin.

Detailed explanation-3: -These long-legged insects are able to walk on the surface of the water because water has a very high surface tension. Surface tension is caused by cohesion of water molecules to one another by hydrogen bonds. (Water has the highest cohesive force of any liquid except that of mercury).

Detailed explanation-4: -This causes an electrostatic attraction between the hydrogen atom in one molecule and the oxygen atom in another. Formed bonds are called hydrogen bonds which lead to strong cohesive forces between the water molecules and high surface tension of water.

Detailed explanation-5: -Because of hydrogen bonding, water can actually support objects that are more dense than it is. Water molecules stick to one another on the surface, which prevents the objects resting on the surface from sinking. This is why water striders and other insects can “walk” on water!