G11) 1.1 Water

The three chemical properties that make water essential for life

adhesion, cohesion, solvent

Cohesion

Water molecules can stick to other water molecules via the formation of hydrogen bonds (creates surface tension).

Adhesion

Water molecules can stick to other polar or charged particles. Lets water flow opposite to gravity (capillary action).

Solvent (solvation)

the process of water surrounding and interacting with solute molecules. Causes the solute to dissolve in water.

4 physical properties that make water essential for life

buoyancy, viscosity, specific heat, thermal conductivity

Buoyancy

The upward force applied to an object in a medium is determined by the density of a medium

Viscosity

The more viscous a fluid, the higher the friction and the resistance to flow. Water has a high viscosity due its hydrogen bonds.

Specific heat

The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree Celsius. Water has a high specific heat capacity due its hydrogen bonds.

Thermal conductivity

Ability of a material to conduct and transfer heat.

Ringed seal (Pusa hispida):

Seals have high buoyancy due to low-density blubber.

Streamlined shape to reduce drag in viscous water.

The seal needs to insulate itself with blubber to maintain body temperatures ( thermal conductivity ).

Seal pups survive in lairs insulated by trapped air due to their lack of blubber.

Black-throated loon (Gavia arctica)

Buoyancy: Large wings to generate lift in less buoyant air.

Viscosity (water): Hydrodynamic to reduce drag.

Viscosity (air): Aerodynamic to reduce drag when flying.

Thermal conductivity (water): Oiled exterior feathers to exclude water.

Thermal conductivity (air): Insulated by air trapped in down feathers.