How does water's surface tension support some organisms?

Water's surface tension allows certain organisms to float, move, and even live on the water's surface.

Surface tension is a property of liquid that allows it to resist an external force. It is caused by the cohesive forces between liquid molecules. In the case of water, its surface tension is particularly high due to the hydrogen bonding between water molecules. This creates a sort of 'skin' on the water's surface that certain organisms can exploit.

Many insects, such as water striders, are able to walk on water due to this surface tension. Their weight is not enough to break the hydrogen bonds between water molecules, so they can move across the surface without sinking. This is also aided by their hydrophobic (water-repelling) legs, which prevent them from getting wet and thus increasing their weight.

Similarly, some spiders can also walk on water, and certain types of lizards can run across it. These creatures have evolved to take advantage of the surface tension of water in their environments, allowing them to escape predators or reach food sources.

Aquatic plants also benefit from water's surface tension. Many have leaves that float on the surface, supported by the high surface tension. This allows the plant to access sunlight for photosynthesis while its roots remain submerged for nutrient uptake.

In addition, some small organisms, known as neuston, live at the air-water interface. They are small enough that the water's surface tension supports them against gravity. This includes various types of bacteria, algae, protozoa, and even small animals like certain insects and spiders.

In conclusion, water's surface tension provides a unique environment that supports a variety of life forms. From insects skimming across a pond to plants floating serenely on a lake, the high surface tension of water is a crucial factor in their survival and behaviour.