CK12 Earth Science

(Marvins-Underground-K-12) #1

  • Water exists on Earth in all three phases: solid, liquid and gas.

  • The water cycle moves water from the hydrosphere to the atmosphere to the land and
    back again.

  • The major processes of the water cycle include evaporation and transpiration, conden-
    sation, precipitation and return to the oceans via runoff and groundwater supplies.


Review Questions



  1. About what percent of the Earth’s water is fresh water?

  2. About what percent of all of Earth’s water is found in groundwater, streams, lakes,
    and rivers?

  3. Explain the following statement: The water on other planets is present in a different
    form than on Earth.

  4. What powers the water cycle?

  5. In what state would water be found at 130oC? What state would water be at -45oC?

  6. Define the words condensation and evaporation.

  7. Summarize the water cycle.

  8. Why do you think the atmosphere is so important to the water cycle?

  9. Suppose the sun grew much stronger in intensity. How would this affect the water
    cycle?


Further Reading / Supplemental Links



Vocabulary


aquifer A layer of rock, sand, or gravel that holds large amounts of groundwater. Humans
often use aquifers as sources of freshwater.


condense To turn from a gas to a liquid.


freshwater Water with a low concentration of salts, which can be consumed and used by
humans.


groundwater Water that is found beneath the Earth’s surface, between soil or rock par-
ticles.


precipitation Water that falls to the Earth from the sky. Precipitation usually takes the
form of rain, but can also occur as snow, sleet, or hail.

Free download pdf