 3 states ◦ Solid ◦ Liquid ◦ Gas  The 3 states of water are controlled by temperature  The amount of water on earth remains the same even if it changes states  70% of Earth’s water is in the ocean

 The sun in the energy force that powers the water cycle  The sun heats oceans, lakes, rivers and causes water to change from liquid state to gaseous state  During evaporation the impurities found in water (salt) are left behind ◦ This is important because 97% of water is salt water found in our oceans

 When temperatures decrease the water vapour (gas) changes back into liquid  Condensation is the opposite of evaporation  Small water droplets are formed in the atmosphere  Collections of water droplets form clouds in the sky or fog at ground level

 Tiny water droplets bounce around in a cloud and as they hit each other they stick together and become larger  The clouds get to heavy and eventually water falls back to the Earth  Precipitation can occur in the form of rain, sleet, snow or hail  Most precipitation falls back into the oceans or onto land

 About 1/3 of water that returns to Earth as precipitation runs off the surface of the land into streams, rives, lakes and oceans  The other 2/3 of precipitation is evaporated, transpired or infilrated into ground water  Surface run off is an important part of the water cycle as it returns water into the bodies (rives, lakes and oceans) where evaporation occurs

 Not all surface run off water flows back into streams, rivers, lakes and oceans. Some of it soaks into the ground  Infiltration is the downward movement of water from the land surface into soil or underlying rocks  This water can replenish aquifers, which store large amounts of fresh water  Some infiltration stays close to the land surface and can seep back into surface water bodies  Some ground water finds openings into the land surface and comes out as fresh water springs

 Water is returned to the atmosphere by plants  Water is absorbed by plants (through the roots) from water found in the soil  The water travels up through the plant and then is evaporated back into the atmosphere from the plants leaves