1. energy to drive the water cycle comes from the sun
water cycle: transfer of water between lithosphere, hydrosphere, atmosphere & biosphere
energy to drive the water cycle comes from the sun

2. water cycle is divided into 4 stages:
1. evaporation: liquid water changes to a gas (water vapor) & rises into the atmosphere
this stage absorbs the sun’s heat energy

3. evaporation occurs from bodies of water, falling precipitation, & soil
plants give off water through transpiration but is still a type of evaporation

4. 2. condensation: water vapor goes back into liquid form (droplets) to form clouds
this stage releases the sun’s heat energy

5. 3. precipitation: clouds can no longer hold the condensed water & it falls back to Earth

6. most precipitation soaks into the ground (called infiltration) & becomes part of the groundwater

7. 4. runoff: water runs over the surface & back into the hydrosphere
runoff occurs when the ground can’t absorb the precipitation

8. runoff can be due to:
steep slope
little or no vegetation
fast & heavy rains
saturated or frozen ground