Trash Revolution

Trash Revolution — page 5
WATER Do you have a reusable water bottle in your backpack that you fill at home or at school Beyond the tap and water fountain where does that water begin Where does it end The Water Cycle It may seem that when it rains water comes from an endless supply in space But rain is part of the water cycle here on Earth The water cycle also called the hydrologic cycle recycles the same water over and over 1 Evaporation The sun provides heat energy The sun evaporates water from the oceans lakes rivers and streams It becomes water vapor 2 Transpiration Water also evaporates from the leaves of plants 3 Condensation Water vapor rises into the atmosphere where the air is colder There the water vapor condenses into clouds 4 Precipitation Air currents move clouds around the Earth Water droplets form inside clouds Droplets fall to Earth as rain and snow precipitation 5 Collection Rain melted ice and snow flow into the ground and waterways Water older than the sun Scientists think water may be even older than the sun Why They have tested water for clues The formula for water is H2O which means two hydrogen atoms are bonded to one oxygen atom But some water molecules also contain an extra molecule called deuterium Deuterium water exists on other planets and moons and in small parts on Earth How did it get here Scientists think it may have traveled in a giant cloud across the solar system before the sun began to burn 4.6 billion years ago Tastes pretty fresh for water that’s billions of years old doesn’t it 8