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Water Cycle.pptx
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- 2. Evaporation Energy from thesun heats up the surface of the Earth, causing the temperature of the water in our rivers, lakes and oceans to rise. When this happens, some of the water “evaporates” into the air, turning into a gas called “vapour“. Plants and trees also lose water to the atmosphere through their leaves. This process is known as “transpiration“.
- 3. Condensation As water vapourrises up high into the sky, it cools and turns back into a liquid, forming clouds. This process is called “condensation“. Currents high up in the air move these clouds around the globe.
- 4. Precipitation When too muchwater has condensed, the water droplets in the clouds become too big and heavy for the air to hold them. And so they fall back down to Earth as rain, snow, hail or sleet, a process known as “precipitation“.
- 5. Evaporation increases ifwarm air blows across the water surface The winds carry the water vapour across the ocean and land. Then warm air rises, cools, and it leads to condensation
- 6. If warm airblows from the ocean to mountains, it rises up and then cools quickly. That is why clouds often form over the mountain near the sea.
- 7. When a cloudbecomes full of liquid water, it falls from the sky as rain or snow—also known as precipitation. Rain and snow then fill lakes and streams, and the process starts all over again.
- 8. Groundwater If water drainsthrough cracks in rocks or soaks through the spaces between particles, it remains under the ground and called groundwater. Gravity draws water lower in the ground
- 9. Water run-off (surfacerun off) Water gathers and flow over the ground to form stream or river Gravity causes water to move downward and sidways.
- 10. Water run-off formation 1.During the spring, as the ground temperature rises, snow melts and forms rivers. This occurs in mountain areas 2. When snow falls in highlands, it squeezes and turns into the ice called glacier. Downhill end of the glacier melts and form river.
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- 12. Science in contextquestions 1. Why do scientists sample ice core? 2. How scientists can know the atmosphere composition of prehistoric time? 3. Have human activity affected the atmosphere? How?