The Water Cycle

• The water cycle is an example of a material cycle, where H2O is continuously moved around the planet.
• This process is powered by the energy from the sun, which enables evaporation to occur.
• Evaporation refers to the process where water at the surface (e.g. oceans, lakes) turns into water vapour and rises into the atmosphere.
• Plants play a major role in the cycle through the process of transpiration, where water absorbed by the roots evaporate from the leaves.
• Condensation happens when the risen water vapour cools down and transforms back into liquid droplets, accumulating in clouds.
• Precipitation occurs when the droplets in the clouds become too heavy and fall back to the earth’s surface as rain, hail, snow, or sleet.
• When rain falls on the land, some of it will be absorbed by the soil, a process called infiltration.
• Some of the infiltrated water will be used by plants, while some will end up in rivers and subsequently the oceans, via a process known as surface runoff.
• Groundwater, which is water located beneath the Earth’s surface in soil pore spaces and in the fractures of rock formations, may also slowly move to the oceans, contributing to the water cycle.
• Remember, the water cycle represents a perfect balance where the amount of water evaporating is equal to the amount of water returning to the Earth’s surface.
• Understanding the intricacies of the water cycle is necessary as it has huge implications for weather patterns, climate change, and sustainability.