1. Water Cycle, Cloud Formation, and Severe Weather

2.  The water cycle is the constant cycling of water within the atmosphere and hydrosphere.  Water cycle-  Evaporation- Sun changes liquid water into water vapor  Condensation- water vapor in the air cools and changes back into a liquid  Precipitation- tiny water droplets, making clouds, combine and fall back to earth as rain, sleet, snow, or hail Water Cycle

4. Cloud Formation  As bodies of water absorb heat energy, the water evaporates, forming clouds.  Terms-  Humidity- moisture in the air  Saturation- state of containing as much of another substance as possible at a given pressure or temperature  Dew point- temperature at which condensation occurs

5.  Warm, moist, air is forced upward, expands and cools.  As air cools, the amount of water vapor needed for saturation decreases and the relative humidity increases.  When the relative humidity reaches 100%, the air is saturated.  Water vapor condenses into tiny droplets around small particles such as dust and salt. Some heat, the latent heat of condensation, is given off as the water vapor condenses.  Billions of water droplets form a cloud. Steps in Cloud Formation

6. Cloud Formation

7. Clouds are made of water droplets or ice crystals- NOT water vapor!!