Integrated Science: The Hydrological Cycle

A comprehensive vocabulary review set covering the components, processes, and structures of the hydrological cycle based on Form 2 Integrated Science notes.

Hydrological cycle

The repeated movement of water molecules around the ecosphere by the processes of evaporation, condensation, and precipitation.

Driving forces of the hydrological cycle

Solar energy and gravity, which drive the entire cycle across the Earth.

Earth's water coverage

Water covers over $70\%$ of its surface, making it the only known planet with this characteristic.

The Sun

The ultimate source of energy that radiates energy through space to the Earth, causing it to become heated and driving the water cycle.

Evaporation

A physical process by which moisture is lost directly to the atmosphere from water surfaces, vegetation surfaces, and the soil due to the sun's heat and the effect of air movement.

Factors affecting evaporation

Temperature, wind speed, humidity, and hours of sunshine.

Condensation

The process whereby the cooling of the air results in a decrease in the kinetic energy of water vapour molecules, causing them to slow down and become unable to resist the strong attractive forces between them.

Water droplet formation

The process where cooled molecules slow down, collide, and join together to form a droplet of water.

Clouds

Suspended water droplets and/or ice crystals that form when air has cooled enough to its dew point, causing water vapour to condense back into water droplets and/or ice crystals.

Precipitation

All liquid and frozen forms of water that fall from the sky, including rain, sleet, snow, and hail.

Dew

A form of precipitation that forms directly on surfaces rather than falling from the sky.

Rainfall and snowfall

The only significant precipitation types responsible for moving water from the atmosphere back to the Earth.

Ground water storage

Water that accumulates underground after passing through overlying soil or rock.

Zone of saturation

An underground layer where water reaches an impermeable rock layer and accumulates, filling all available pore spaces.

Water table

The upper boundary of the zone of saturation.