How to explain water cycle to preschoolers?
Well, water cycle in the environment, a hydrological cycle, in other words, is a chain of phenomena. Water, an omnipresent element of the environment and the basic building material of all living organisms, undergoes various transformations. We do not know where it comes from. Or at least, we are not able to say when and how it appeared on the Earth; however, we have two thesis ideas which say about its source. According to one of them, first water resources emerged from magma in innumerable volcanic processes. Water is the result of the reaction of hydrogen atoms carried with oxygen atoms. This is done by solar wind in the Earth’s atmosphere.
Since we do not know the source of water is. And we are not able to distinguish the beginning of water cycle. Let’s start with the biggest water bodies – oceans.
Climate Factors of Water Cycle
Water cycle in the environment is forced by climatic factors: temperature (the Sun) and winds. The Sun heats water in oceans and as the result, the water evaporates. Due to air cycle, water vapor accumulates in various levels of the atmosphere creating clouds. Winds and currents make this store of the condensed vapor move freely all over the Earth. After some time, in favorable conditions (e.g. air cooling), molecules of vapor contained in clouds condense more. Or even freeze and fall on the Earth in the form of precipitation (rain, snow, hail).
Some part of the water which does not soak in soil, flows into rivers and with the rivers it flows into seas and oceans whereas the water which soaks in the upper layers of soil feeds plants and, partly filtered through soil, flows into surface water (water bodies) from which it evaporates or returns to oceans. Groundwater which gathers in the lower layers of soil becomes underground streams. These flow deeply under the surface of the Earth. Or in any event, flow into bigger water bodies and then into oceans.
In every stage of this cycle, evaporation takes place. Thus not only are oceans responsible for the creation of clouds. But also all water bodies and all life and civilization processes associated with water.