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Water Cycle Presentation

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Water Cycle Presentation

  1. 1. The Water Cycle<br />7th Grade Science<br />
  2. 2. “Water Cycle Jump” Video<br />Water Cycle Jump<br />
  3. 3.
  4. 4. Water<br />3 states<br />Solid <br />Liquid<br />Gas <br />The 3 states of water are determined mostly by temperature.<br />Even though water is constantly changing states, the total amount of water on Earth remains constant.<br />Over 70% of the Earth’s surface is covered by oceans<br />Water is constantly being cycled between the atmosphere (air), hydrosphere (water), and lithosphere (land).<br />
  5. 5. Evaporation<br />The sun (temperature) is the energy force that powers the water cycle<br />It heats oceans, lakes, rivers and causes water to change from the liquid state to the gaseous state<br />The oceans contribute to about 80-90% of the water vapor in the atmosphere.<br />During evaporation, the impurities (for example, Salt) are left behind. <br />This is important because about 97% of the water on Earth is salt water (oceans) and only 3% is freshwater (rivers, streams, lakes, ponds, and in the ground).<br />
  6. 6. Condensation<br />When atmospheric temperature decreases, the water vapor (gas) changes back into a liquid.<br />Condensation is the opposite of evaporation.<br />Small water droplets are formed in the atmosphere.<br />Collections of water droplets form clouds in the sky or fog at ground level.<br />You can see condensation on drinks in the summertime or leaves in the morning.<br />
  7. 7. Precipitation<br />Tiny water droplets bounce around in a cloud and as they hit each other, they stick together and become larger.<br />The clouds get heavy and eventually water falls back to the Earth.<br />Precipitation can occur in the form of rain, freezing rain, sleet, snow, or hail.<br />Most precipitation falls back into the oceans or onto land. If precipitation falls in the form of snow it can accumulate in the form of ice caps or glaciers.<br />Most of the condensed water in clouds does not actually fall as precipitation.<br />
  8. 8. Surface Runoff<br />About 1/3 of the water that returns to the Earth as precipitation runs off the surface of the land, down hill, into streams, rivers, lakes, and oceans.<br />The other 2/3 of precipitation is evaporated, transpired, or is infiltrated into ground water.<br />Surface Runoff is a very important part of the water cycle because it returns water once again to the bodies of water, where evaporation occurs.<br />For example, when snow melts<br />
  9. 9. Infiltration<br />Not all surface runoff water flows back into streams, rivers, lakes, and oceans. Some of it soaks into the ground.<br />Infiltration is the downward movement of water from the land surface into soil or underlying rock layers.<br />This water can replenish aquifers, which store large amounts of freshwater that can be removed from the ground using a water well.<br /> Some infiltration stays close to the land surface and can seep back into surface-water bodies <br /> (and the ocean) as<br /> groundwater discharge. <br />Some groundwater finds <br /> openings in the land surface <br /> and comes out as <br /> freshwater springs.<br />
  10. 10. Transpiration<br />Water is returned to the atmosphere by plants.<br />Water is absorbed by plants (usually through the roots) from water that is in the soil. <br />The water travels up through the plant and then is evaporated back into the atmosphere from the plant surface (usually the leaves). <br />
  11. 11. Sublimation<br />Sublimation is the conversion between the solid and gaseous form of water, with no intermediate liquid stage.<br />This occurs when there is low atmospheric pressure.<br />An example of this is when snow and ice change into water vapor in the air without first melting into water.<br />Phase Diagram for Water<br />

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