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00:00Hi kids! Today we will learn about the movement of water on earth, or the water cycle.
00:11So let's start.
00:15Now we know all the parts of water cycle.
00:20That is, evaporation, transpiration, precipitation, condensation, collection, infiltration, and surface water runoff.
00:33Now, let's try to understand the water cycle.
00:38Let's start with the process of evaporation.
00:44Evaporation is the change of liquid state of water to gaseous state.
00:51So, evaporation occurs all over the earth, where water exists.
00:57Water from all water bodies keep on heating and changing to gaseous state.
01:04So, it's the process of evaporation, because of which water from all the water bodies is moving to the air.
01:16And when plants breed, they release water vapors along with oxygen, which is called transpiration.
01:26Sometimes, snow also directly changes to water vapors, and it's called sublimation.
01:35So, there are three processes by which water is getting converted to gaseous state.
01:43Evaporation, transpiration, and sublimation.
01:50So there are water vapors all over there in the air.
01:55And when these water vapors rises high in the air, they cool down and changes to liquid state or condense, and forms big clouds in the air.
02:08And it's the clouds that result in different forms of precipitation.
02:14That is falling of water from the sky in the form of water, snow, hail.
02:22So, because of precipitation, the evaporated water again becomes a part of water bodies.
02:31Some water seeps down the earth's surface, which is called infiltration, and replenishes the aquifers, which can store fresh water for long periods of time.
02:45Precipitation, such as snowfall, accumulates the water on hills and mountains as ice caps and glaciers.
02:56Now, when the weather changes, the water accumulated on hills and mountains in the form of ice or snow melts back and flows to the ground as rivers and streams.
03:11And this flowing down of water is called surface runoffs.
03:16Not all runoff flows into rivers. Much of it soaks into the ground as infiltration.
03:25Some groundwater finds openings in the land surface and comes out as fresh water springs.
03:33Finally, the rivers again joins with the big seas, and oceans form where most of the evaporation occurs.
03:43So water keeps changing its states and place, and we see there is a continuous movement of water on earth that goes on and on.
03:56Water cycle is also known as hydrologic cycle or H2O cycle.
04:04And the processes by which water changes its states and place are evaporation, transpiration, condensation, precipitation, infiltration, and surface runoff.
04:21All these processes also involve exchange of energy, which is why it also leads to temperature changes, like evaporation cools down the atmosphere.
04:37Condensation warms up the atmosphere.
04:43The water cycle is very important for the maintenance of most life and ecosystems on the planet.
04:52Now let's learn what is the source of energy for water cycle.
04:59It is the sun that heats up the water in oceans and other water bodies and leads to evaporation.
05:08Wind is also the driving force behind clouds that leads to precipitation.
05:15And wind too is result of differential heating of earth due to sun.
05:22So what we learned?
05:24The ultimate source of energy is sun.
05:29So kids, today we learned what is water cycle.
05:34Now you may go ahead and take a quiz to learn more.
05:38Bye-bye.