Hydrological cycle

Master the Hydrological Cycle! Learn about evaporation, condensation, and precipitation in this engaging science worksheet.

This worksheet will help you understand the Hydrological Cycle. Why do we call the Hydrological Cycle a closed system? •The Sun(solar energy) powers this cycle. By heating the oceans, lakes, rivers and the earth’s surface, water is changed into a gas by the process of evaporation. Most of the water vapour comes from the oceans, especially in tropical waters. The atmosphere receives about 85% of its moisture from the oceans and 15% from the land by evaporation. Water can be lost from plants and surface drainage through the process of evapotranspiration. •All this moisture-laden air is transferred by Global Winds. • •This moisture Condenses, when cooling takes place and clouds form. •Eventually the clouds can no longer hold any more moisture and precipitation falls as rain or snow depending on the altitude. •Much of this precipitation falls as rain over the oceans and then the cycle is completed quickly. Over high latitudes and mountains, however snow may accumulate in glaciers and icecaps and therefore can be held in storage for a long period of time.When rainfall lands on the ground it makes it way overland to the sea in a variety of different ways.First of all it infiltrates the soil and, if the soil is on a slope, the water slowly moves down slope as throughflow. If the underlying rock is permeable, the water percolates downwards, filling it until it is saturated.This saturated rock is called groundwater, which acts as a store slowly releasing the water back into the sea as springs and rivers.Water is also returned to oceans, rivers, lakes by surface run-off, which is much faster.