Water Cycle

1. Sun- our star and the source of all energy on the Earth
2. Solar energy - is the energy of the sun.
3. Radiation- how the Sun’s energy moves through space, as  radiation strikes the Earth’s surface, it changes into heat.
4. hydrologic or water cycle- endless process in which water evaporates from oceans and lakes, condenses into clouds and returns to the Earth as precipitation.
5. Solar energy -heats the water and drives the water cycle
6. Three states of water- solid, liquid, and gas
7. three major steps of hydrologic cycle- evaporation/transpiration, condensation, and precipitation
8.  Energy- is either added to or taken away during each step to cause the changes!
9. eVAPORation- water absorbs enough heat to change into a gas called water vapor.  Water vapor is INVISIBLE!!!  Molecules gain energy, energy is added.
10.  We CANNOT see water vapor!
11.  salt- stays behind in the ocean and ONLY the water evaporates.  Oceans provide most of the water vapor in the atmosphere.
12. transpiration- plants losing water vapor to the air through leaves (plant sweat!)  Molecules gain energy, energy is added.
13. Condensation- water vapor cooling down or losing enough energy to change into tiny droplets of water.  Cooling causes condensation. Molecules lose energy, energy is lost.
14. clouds-are caused by condensation.  Clouds are tiny droplets of water, they are NOT water vapor!

15. Precipitation- water falling from the sky as rain, snow, sleet, or hail.  Droplets of water get large enough for gravity to make them fall to the Earth.